check for valid options in validate method

This change prevents a certain class of user error which results when
mistakenly using the `validate` class method instead of the `validates`
class method.

Only apply when all arguments are symbols, because some validations use
the `validate` method and pass in additional options, namely the
`LenghValidator` via the `ActiveMode::Validations::validates_with`
method.
Merge pull request #16210 from sonnym/assert_valid_keys_in_validate

Check for valid options in validate method