Corrected few Kotlin style issues

[singhrishiranjan]

Purpose / Description

Cleanup: Fixed a few Kotlin style warnings given by Android Studio Inspection

Fixes

• Fixes Cleanup: Fix Android Studio warnings #20278

Approach

1. Range check simplification
2. Null-safety handling for view
3. Substring API improvement

How Has This Been Tested?

Project built and ran successfully

Learning

This was my first ever contribution on GitHub. I learnt how one can quick fix some errors automatically through IDE.

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[lukstbit]

Thanks and welcome.
I left a request for a small change, the rest looks good.

[lukstbit]

It would be useful if you could squash the two commits together, but other than that this looks good, thanks.