Simplify imagery state management in ID editor

[sumitdahal7]

What type of PR is this? (check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation
• 🧑‍💻 Refactor
• ✅ Test
• 🤖 Build or CI
• ❓ Other (please specify)

Related Issue

Fixes #7255

Describe this PR

This PR refactors the imagery state management in the iD editor component and fixes an issue where imagery offsets
persisted between projects/tasks.

Key Changes:

• Simplified Imagery State: Removed the redundant customImageryIsSet local state. The logic now directly checks for
  imagery types and iDContext availability, making the component more predictable and easier to maintain.
• Fixed Imagery Offset Persistence: Added logic to explicitly reset the imagery offset to [0, 0] if no offset
  parameters are provided in extraIdParams. Previously, the editor would retain the offset from a previously
  visited task or project, leading to incorrect alignment.
• Default Imagery Enforcement: Ensured that if a project has no specific imagery configured, the editor defaults to
  'Bing' and resets any previous custom background settings.
• Improved Null Safety: Added guard clauses to ensure iDContext.background() is fully loaded before attempting

Screenshots

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[danieldegroot2]

cc @tyrasd (feel free to take a look at these changes)