Mobile Number Validation Bug: Invalid Numbers Passing Validation

[DraKen0009]

Describe the bug
The mobile number validation allows invalid phone numbers like +000000000000 and +9876543210123456, which ideally should not be considered valid. This issue is due to a bug in the regular expression used in the validation logic.

To Reproduce
Steps to reproduce the behavior:

1. Go to the mobile number validation function located here.
2. Try validating phone numbers like +000000000000 or +9876543210123456.
3. Observe that these numbers are incorrectly validated as valid.

Expected behavior
Phone numbers with formats like +000000000000 and overly long sequences like +9876543210123456 should not pass validation.

Additional context
This issue seems to be caused by the current regex pattern: regex link.

[DraKen0009]

I think we should add some proper validations instead of using regex pattern bcz

1. Stricter regex fails for some valid numbers
2. Simpler regex validates the invalid numbers

cc: @sainak