Return instance version from server info if available

[PattaFeuFeu]

Description

#270 accidentally added a change where the instance version was no longer returned even if we got one from the NodeInfoClient, so we always fell back to getting the instance info through the Mastodon API.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Dependency update / replacement

How Has This Been Tested?

gradle check

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have made corresponding changes to the documentation if necessary
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[codecov]

Codecov Report

Merging #290 (39ceeb9) into master (d80d2e1) will decrease coverage by 0.02%.
The diff coverage is 50.00%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #290      +/-   ##
============================================
- Coverage     35.89%   35.88%   -0.02%     
  Complexity      348      348              
============================================
  Files           101      101              
  Lines          3034     3035       +1     
  Branches        183      184       +1     
============================================
  Hits           1089     1089              
- Misses         1825     1826       +1     
  Partials        120      120              

Files	Coverage Δ
...e/src/main/kotlin/social/bigbone/MastodonClient.kt	32.11% <50.00%> (-0.12%)	⬇️

[bocops]

Looks good!

[andregasser]

Thanks for the review @bocops 👍