Issue:
Bug: BE Password specification



Make password have
Minimum number of characters.
At least one number, uppercase & lowercase characters and symbol. (This check is there in FE but not in BE).

Pull request description:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [X] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
Closes #4412 


### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!--
Provide links to the files with corresponding changes.

Following are the paths where you can find config files:
1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->



## Motivation and Context
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Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

If you don't have an issue, we'd recommend starting with one first so the PR
can focus on the implementation (unless it is an obvious bug or documentation fix
that will have little conversation).
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The mandatory condition for the password field was just not be empty . Following the PR, the password field will be subject to the following checks:
1.The password must be between 8 and 50 characters in length.
2.It must include at least one uppercase character.
3.It must include at least one lowercase character.
4.It must include at least one special character.
5.It must include at least one numeric character.

## How did you test it?
<!--
Did you write an integration/unit/API test to verify the code changes?
Or did you test this change manually (provide relevant screenshots)?
-->
1. Signup API ( local testing) 
```
curl --location 'http://localhost:8080/user/signup' \
--header 'Content-Type: application/json' \
--data-raw '{
    "email": "email value",
    "password": "456667sdvh",
    "country": "IN"
}'
```
Failure case response 
```
{
    "error": {
        "type": "invalid_request",
        "message": "Invalid Password",
        "code": "UR_09"
    }
}
```
2. Reset Password API (local testing)
```
curl --location 'http://localhost:8080/user/reset_password' \
--header 'Content-Type: application/json' \
--data '{
    "password": "456667sdvd",
    "token":"token from email after clicking Reset password in dashboard"
}'
```
Failure case response 
```
{
    "error": {
        "type": "invalid_request",
        "message": "Invalid Password",
        "code": "UR_09"
    }
}
``` 

## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt --all`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible


Testing:

1. Signup API ( local testing) 
```
curl --location 'http://localhost:8080/user/signup' \
--header 'Content-Type: application/json' \
--data-raw '{
    "email": "email value",
    "password": "456667sdvh",
    "country": "IN"
}'
```
Failure case response 
```
{
    "error": {
        "type": "invalid_request",
        "message": "Invalid Password",
        "code": "UR_09"
    }
}
```
2. Reset Password API (local testing)
```
curl --location 'http://localhost:8080/user/reset_password' \
--header 'Content-Type: application/json' \
--data '{
    "password": "456667sdvd",
    "token":"token from email after clicking Reset password in dashboard"
}'
```
Failure case response 
```
{
    "error": {
        "type": "invalid_request",
        "message": "Invalid Password",
        "code": "UR_09"
    }
}
``` 

Patch:
diff --git a/crates/router/src/consts/user.rs b/crates/router/src/consts/user.rs
index 1cda969f780..f14610649f4 100644
--- a/crates/router/src/consts/user.rs
+++ b/crates/router/src/consts/user.rs
@@ -1,3 +1,5 @@
 pub const MAX_NAME_LENGTH: usize = 70;
 pub const MAX_COMPANY_NAME_LENGTH: usize = 70;
 pub const BUSINESS_EMAIL: &str = "biz@hyperswitch.io";
+pub const MAX_PASSWORD_LENGTH: usize = 70;
+pub const MIN_PASSWORD_LENGTH: usize = 8;
diff --git a/crates/router/src/types/domain/user.rs b/crates/router/src/types/domain/user.rs
index fab02df88ba..0b971d82032 100644
--- a/crates/router/src/types/domain/user.rs
+++ b/crates/router/src/types/domain/user.rs
@@ -155,7 +155,32 @@ pub struct UserPassword(Secret<String>);
 impl UserPassword {
     pub fn new(password: Secret<String>) -> UserResult<Self> {
         let password = password.expose();
-        if password.is_empty() {
+
+        let mut has_upper_case = false;
+        let mut has_lower_case = false;
+        let mut has_numeric_value = false;
+        let mut has_special_character = false;
+        let mut has_whitespace = false;
+
+        for c in password.chars() {
+            has_upper_case = has_upper_case || c.is_uppercase();
+            has_lower_case = has_lower_case || c.is_lowercase();
+            has_numeric_value = has_numeric_value || c.is_numeric();
+            has_special_character =
+                has_special_character || !(c.is_alphanumeric() && c.is_whitespace());
+            has_whitespace = has_whitespace || c.is_whitespace();
+        }
+
+        let is_password_format_valid = has_upper_case
+            && has_lower_case
+            && has_numeric_value
+            && has_special_character
+            && !has_whitespace;
+
+        let is_too_long = password.graphemes(true).count() > consts::user::MAX_PASSWORD_LENGTH;
+        let is_too_short = password.graphemes(true).count() < consts::user::MIN_PASSWORD_LENGTH;
+
+        if is_too_short || is_too_long || !is_password_format_valid {
             Err(UserErrors::PasswordParsingError.into())
         } else {
             Ok(Self(password.into()))