Add state management for map markers and circles in GameplayMap

[3TTemi]

Summary

1. This pull request first addresses the issue where the challenge location does not refresh when initially null, often defaulting to a fallback location. The changes ensure that the map dynamically updates to reflect the correct challenge location.

• Implemented state management for map markers and circles to handle dynamic updates.
• Updated _updateMapMarkers to refresh markers and circles when targetLocation changes.

2. This pull request also addresses behavior where the map area is pushed to splash page but it is nested in the gameplay page still.

• Remove the StreamBuilder from GameplayMap entirely to remove duplicate handling with BottomNavBar

Remaining TODOs:

• Integrated markers and circles with the GoogleMap widget to ensure accurate location representation.

Test Plan

Test the map's behavior when targetLocation is initially null and later updated to ensure it reflects the correct location.

Confirm that the map does not default to the fallback location once the targetLocation is set.

Ensure disconnecting from gameplay bring users back to splash page without any nested elements

[dti-github-bot]

[diff-counting] Significant lines: 90.