Issue:
[BUGFIX] Replacing the occurrences of `gen_range` with a safe alternative

## Description

Following up with the issue https://github.com/rust-random/rand/issues/1326 created by @lsampras. The function `gen_range` in itself can cause panics and error handling isn't done for some cases. This is a unpredictable behaviour and needs to be replaced with a safe alternative which allows for error handling and recoverability.

## Objective

- Deciding open a safe alternative for `gen_range` while keeping the behaviour relatively same
- Replacing the occurrences of `gen_range` with the decided safe alternative

## Guidelines

- Please mention the approach for solving the above mentioned issue and reasoning of it being recoverable. 

Resolution:
<think>
PR Context:
- Title: fix(router/scheduler): replace the occurrences of gen_range with a safer alternative
- Merged: 2023-09-12T09:11:47Z
- Files changed: 4 files
- Commits: 5 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description

This is a bugfix for issue [1754](https://github.com/juspay/hyperswitch/issues/1754).
I have replaced the instances of `gen_range()` with `Uniform.sample`.
This should reduce the risk of `gen_range()` throwing a `panic!`.

### Additional Changes

- [ ] This PR modifies the API
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** fix(router/scheduler): replace the occurrences of gen_range with a safer alternative (#2126)
Files to modify:


**crates/router/src/routes/dummy_connector/utils.rs**
  Modify existing code

**crates/scheduler/src/consumer.rs**
  Modify existing code

**crates/scheduler/src/producer.rs**
  Modify existing code