chore: Remove current dark mode implementation

[manishraj-003]

Fixes #2999

Changes

• Replaced conditional theme logic with: themeMode: ThemeMode.light
• Set both theme and darkTheme to use AppTheme.lightTheme
• Ensures consistent UI and removes unexpected dark mode usage.

Results

• App always stays in Light mode, even when device is in Dark mode
• Verified on: • Android Emulator (API 34) • System Dark Mode ON/OFF • App restart
• No visual/UI regressions introduced

Screenshots / Recordings

The below recording shows the ui of the app when the system dark mode is 'ON' and 'OFF'. https://github.com/user-attachments/assets/1aea9d84-fb25-4783-9cac-067bdc4920e5 Checklist:

• [x] No hard coding: I have used values from constants.dart or localization files instead of hard-coded values.
• [x] No end of file edits: No modifications done at end of resource files.
• [x] Code reformatting: I have formatted the code using dart format or the IDE formatter.
• [x] Code analysis: My code passes checks run in flutter analyze and tests run in flutter test.

Summary by Sourcery

Enforce a consistent light UI theme across platforms and align desktop plugin registration with existing geolocation dependencies.

New Features:

• Enable geolocation plugin registration on Windows and macOS via geolocator platform plugins.

Enhancements:

• Update Android night-mode launch and normal themes to use light variants so the app always presents a light theme regardless of system dark mode settings.

Build:

• Add Windows CMake plugin list entry for the geolocator Windows plugin.