Reset route and routeBufferGeoJson as part of MapboxNativeNavigatorImpl#reset

[Guardiola31337]

Description

Resets route and routeBufferGeoJson as part of MapboxNativeNavigatorImpl#reset

Follow up from #2850 (comment)

• I have added any issue links
• I have added all related labels (bug, feature, new API(s), SEMVER, etc.)
• I have added the appropriate milestone and project boards

Goal

Tailwork from #2850

Implementation

override fun reset() {
    navigator = Navigator()
    route = null
    routeBufferGeoJson = null
}

Testing

Please describe the manual tests that you ran to verify your changes

• I have tested locally (including SNAPSHOT upstream dependencies if needed) through testapp/demo app and run all activities to avoid regressions
• I have tested via a test drive, or a simulation/mock location app
• New and existing unit tests pass locally with my changes

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have updated the CHANGELOG including this PR

cc @kmadsen

[codecov-io]

Codecov Report

Merging #2852 into master will increase coverage by 0.40%.
The diff coverage is 57.35%.

@@             Coverage Diff              @@
##             master    #2852      +/-   ##
============================================
+ Coverage     35.00%   35.41%   +0.40%     
+ Complexity     2107     2101       -6     
============================================
  Files           541      544       +3     
  Lines         19422    19541     +119     
  Branches       1841     1841              
============================================
+ Hits           6799     6920     +121     
+ Misses        11807    11794      -13     
- Partials        816      827      +11