Fix lint in Main.kt

[poliver]

These have been bugging me for a while. Scaffold padding shouldn't really matter in this case, but string res access may actually not behave correctly due to LocalContext reads not being invalidated on config changes. LocalResources is a better way to access strings in this case.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.39%. Comparing base (88ba0aa) to head (1114436).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
app/src/main/java/com/geeksville/mesh/ui/Main.kt	0.00%	9 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##            main   #3484      +/-   ##
========================================
- Coverage   0.39%   0.39%   -0.01%     
========================================
  Files        300     300              
  Lines      17874   17875       +1     
  Branches    2140    2140              
========================================
  Hits          71      71              
- Misses     17787   17788       +1     
  Partials      16      16              

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