[Android] Show Battery Optimization settings when:

[AenBleidd]

1. Battery Optimization settings are available
2. and application was not already set to ignore Battery Optimization
3. and these settings were not shown before

This fixes #4420

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 31 lines in your changes missing coverage. Please review.

Project coverage is 10.84%. Comparing base (b2a5bbc) to head (612c836).
Report is 797 commits behind head on master.

Files with missing lines	Patch %	Lines
.../src/main/java/edu/berkeley/boinc/TasksFragment.kt	0.00%	31 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5333      +/-   ##
============================================
- Coverage     10.85%   10.84%   -0.01%     
  Complexity     1064     1064              
============================================
  Files           279      279              
  Lines         36005    36036      +31     
  Branches       8326     8331       +5     
============================================
  Hits           3909     3909              
- Misses        31704    31735      +31     
  Partials        392      392              

Files with missing lines	Coverage Δ
.../src/main/java/edu/berkeley/boinc/TasksFragment.kt	0.00% <0.00%> (ø)