[Plugin] Deprecate TestRunFinished(Instant)

[mpkorstanje]

Since v6 the TestRunFinished event always contains a result when emitted by
Cucumber.

[codecov]

Codecov Report

Merging #2169 into main will increase coverage by 0.01%.
The diff coverage is 25.00%.

@@             Coverage Diff              @@
##               main    #2169      +/-   ##
============================================
+ Coverage     82.78%   82.79%   +0.01%     
  Complexity     2313     2313              
============================================
  Files           306      306              
  Lines          8293     8295       +2     
  Branches        767      767              
============================================
+ Hits           6865     6868       +3     
+ Misses         1119     1118       -1     
  Partials        309      309              

Impacted Files	Coverage Δ	Complexity Δ
...java/io/cucumber/plugin/event/TestRunFinished.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...in/java/io/cucumber/core/plugin/PluginFactory.java	74.46% <100.00%> (+2.42%)	25.00 <0.00> (ø)

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