[fenix] For https://github.com/mozilla-mobile/fenix/issues/13959: improve custom...

[fenix] For https://github.com/mozilla-mobile/fenix/issues/13959: improve custom detekt violation output.

Before it used to output the violations all one one line. Now it looks
like:
```
MozillaStrictModeSuppression:
    'import mozilla.components.support.ktx.android.os.resetAfter' at
(17,1) in /StrictModeManager.kt
    Please use `components.strictMode.resetAfter` instead because it has
performance improvements and additional code to monitor for performance
regressions.

MozillaStrictModeSuppression:
    'setThreadPolicy(threadPolicy.build())' at (56,24) in
/StrictModeManager.kt
    Please use `components.strictMode.resetAfter` instead because it has
performance improvements and additional code to monitor for performance
regressions.

MozillaStrictModeSuppression:
    'setVmPolicy(builder.build())' at (71,24) in /StrictModeManager.kt
    NOT YET IMPLEMENTED: please consult the perf team about
implementing`StrictModeManager.resetAfter`: we want to understand the
performance implications of suppressing setVmPolicy before allowing it.
```