Make MultiRuleCollector.kt consistent with the DoubleMutabilityForCollection rule

[schalkms]

Closes #4042

[codecov]

Codecov Report

Merging #4405 (eb69861) into main (48a28fc) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##               main    #4405      +/-   ##
============================================
+ Coverage     84.23%   84.28%   +0.04%     
- Complexity     3259     3280      +21     
============================================
  Files           474      474              
  Lines         10323    10425     +102     
  Branches       1825     1859      +34     
============================================
+ Hits           8696     8787      +91     
- Misses          666      670       +4     
- Partials        961      968       +7     

Impacted Files	Coverage Δ
.../detekt/generator/collection/MultiRuleCollector.kt	74.62% <100.00%> (ø)
.../gitlab/arturbosch/detekt/rules/empty/EmptyRule.kt	92.30% <0.00%> (-3.15%)	⬇️
...etekt/rules/style/optional/MandatoryBracesLoops.kt	73.33% <0.00%> (-2.53%)	⬇️
...ab/arturbosch/detekt/core/config/ValidateConfig.kt	98.64% <0.00%> (-1.36%)	⬇️
...n/kotlin/io/gitlab/arturbosch/detekt/api/Entity.kt	75.00% <0.00%> (-1.20%)	⬇️
.../gitlab/arturbosch/detekt/api/internal/Versions.kt	87.50% <0.00%> (ø)
...n/io/github/detekt/report/html/HtmlOutputReport.kt	95.55% <0.00%> (ø)
.../arturbosch/detekt/generator/out/AbstractWriter.kt	0.00% <0.00%> (ø)
...rturbosch/detekt/rules/style/StyleGuideProvider.kt	100.00% <0.00%> (ø)
.../detekt/rules/exceptions/ObjectExtendsThrowable.kt	80.95% <0.00%> (ø)
... and 15 more

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