Fix zoom in draw area task

[andreia-ferreira]

Fixes #3833

When entering a draw area task, the map would jump to the max zoom instead of keeping the current zoom value of the home screen. This would happen because, since in the beginning there is only one draft vertex, there were no bounds to zoom to, so it would jump to the max zoom.

getDefaultViewPort() was added to the DrawAreaTaskViewModel to decide the camera position, and if there is only 1 point, it will only center on it. The setDefaultViewPort call site was also modified so that it will only be triggered once after the STARTED state, instead of every time it entered that state as it was previously

Before

Screen_recording_20260831_174746.webm

After

Screen_recording_20260831_173314.webm

@shobhitagarwal1612 PTAL?

[codecov]

Codecov Report

❌ Patch coverage is 46.15385% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.47%. Comparing base (94baf3c) to head (3d4f25c).

Files with missing lines	Patch %	Lines
...ollection/tasks/polygon/DrawAreaTaskMapFragment.kt	25.00%	3 Missing ⚠️
.../android/ui/common/AbstractMapContainerFragment.kt	0.00%	1 Missing ⚠️
...ui/datacollection/tasks/AbstractTaskMapFragment.kt	0.00%	1 Missing ⚠️
...tacollection/tasks/point/DropPinTaskMapFragment.kt	0.00%	1 Missing ⚠️
...acollection/tasks/polygon/DrawAreaTaskViewModel.kt	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3913      +/-   ##
============================================
+ Coverage     69.36%   69.47%   +0.10%     
- Complexity     1963     1966       +3     
============================================
  Files           412      412              
  Lines         11015    11018       +3     
  Branches       1453     1453              
============================================
+ Hits           7641     7655      +14     
+ Misses         2624     2612      -12     
- Partials        750      751       +1     

Files with missing lines	Coverage Δ
.../android/ui/common/AbstractMapContainerFragment.kt	15.49% <0.00%> (+0.42%)	⬆️
...ui/datacollection/tasks/AbstractTaskMapFragment.kt	60.27% <0.00%> (ø)
...tacollection/tasks/point/DropPinTaskMapFragment.kt	14.28% <0.00%> (ø)
...acollection/tasks/polygon/DrawAreaTaskViewModel.kt	82.11% <83.33%> (+0.05%)	⬆️
...ollection/tasks/polygon/DrawAreaTaskMapFragment.kt	52.38% <25.00%> (+2.38%)	⬆️

... and 1 file with indirect coverage changes

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