PAINTROID-810 Update AGP and Kotlin versions

[Amit-Matth]

This PR resolves the Android build dependency warnings by updating the Android Gradle Plugin and Kotlin to their modern, supported versions (AGP 8.7.0 and Kotlin 2.1.0).

PAINTROID-810

New Features and Enhancements

• None

Refactorings and Bug Fixes

• Upgraded Android Gradle Plugin (AGP) from 8.5.0 to 8.7.0
• Upgraded Kotlin version from 1.9.24 to 2.1.0
• Resolved Gradle compatibility warnings introduced by recent Flutter upgrade

Checklist

Your checklist for this pull request

Please review the contributing guidelines and wiki pages of this repository.

• Include the name of the Jira ticket in the PR’s title
• Add the link to the ticket in Jira in the description of the PR
• Include a summary of the changes plus the relevant context
• Choose the proper base branch (develop)
• Confirm that the changes follow the project’s coding guidelines (Wiki)
• Verify that the changes generate no compiler or linter warnings
• Perform a self-review of the changes
• Verify to commit no other files than the intentionally changed ones
• Include reasonable and readable tests verifying the added or changed behavior (N/A - build config update)
• Confirm that new and existing tests pass locally
• Check that the commits’ message style matches the project’s guideline
• Verify that your changes do not have any conflicts with the base branch
• After the PR, verify that all CI checks have passed
• Add new information to the Wiki (N/A)