fix: improve solhint custom rules and remove TODOs

[crStiv]

This commit improves the solhint custom rules by:

1. Expanding visibility check for constant variables to include internal constants
2. Re-enabling and fixing the no-external-virtual rule with:
   • Skip checks for constructors and interfaces
   • Improved error message with actionable suggestion
   • Fixed comparison operator

Both TODO comments have been addressed while maintaining the codebase's
coding standards and improving the overall code quality checks.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 4f95017

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[Amxx]

NOTE: prettier rules say that receive and fallback function MUST be external. This creates a conflicts if they are virtual. This leaves us tree options:

• remove virtual from receive/fallback: bit no for me!
• change the prettier config
• (what I did here) skip the rule for receive and fallback functions.