Fix to navigating long urls on mobile devices.

[Aman071106]

PR Description

This PR addresses issue #825 regarding the difficulty of navigating and editing long URLs on mobile devices.

Changes Implemented:

• Introduced a Pinch-out gesture on the main URL field to trigger an expanded editing view.
• Added ExpandedURLEditor widget, displayed as a Dialog:
  • Supports text wrapping for better visibility of long URLs (unlike the single-line main field).
  • Includes Navigation Buttons (< and >) to quickly jump the cursor between URL separators (e.g., /, ., ?, &).
  • Ensures focus is retained when using navigation buttons, keeping the keyboard active.
  • Includes Copy and Clear utility buttons.
• Modified EnvironmentTriggerField to support maxLines configuration.
• Ensured the main URL field retains its original single-line height (maxLines: 1) to preserve the existing UI layout.

Related Issues

• Closes [Mobile] Difficulty in Navigating URL Field for longer URLs #825

Checklist

• I have gone through the contributing guide
• I have updated my branch and synced it with project main branch before making this PR
• I am using the latest Flutter stable branch (run flutter upgrade and verify)
• I have run the tests (flutter test) and all tests are passing

Added/updated tests?

• Yes
• No, ui fix added video.

OS on which you have developed and tested the feature?

• Windows
• macOS
• Linux