update InvalidPackageDeclaration to report if rootPackage is not present

[mateot1]

This should fix the issue I just opened here: #4483

[codecov]

Codecov Report

Merging #4484 (7beeee0) into main (56e7fa9) will increase coverage by 84.44%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             main    #4484       +/-   ##
===========================================
+ Coverage        0   84.44%   +84.44%     
- Complexity      0     3329     +3329     
===========================================
  Files           0      479      +479     
  Lines           0    11147    +11147     
  Branches        0     2040     +2040     
===========================================
+ Hits            0     9413     +9413     
- Misses          0      700      +700     
- Partials        0     1034     +1034     

Impacted Files	Coverage Δ
...h/detekt/rules/naming/InvalidPackageDeclaration.kt	96.77% <100.00%> (ø)
.../arturbosch/detekt/core/baseline/BaselineFacade.kt	85.71% <0.00%> (ø)
.../arturbosch/detekt/core/config/ConfigValidators.kt	84.21% <0.00%> (ø)
...ab/arturbosch/detekt/rules/bugs/HasPlatformType.kt	68.00% <0.00%> (ø)
.../detekt/rules/naming/ConstructorParameterNaming.kt	96.77% <0.00%> (ø)
...ls/src/main/kotlin/io/github/detekt/psi/KtFiles.kt	75.00% <0.00%> (ø)
...lab/arturbosch/detekt/core/rules/RuleSetLocator.kt	87.50% <0.00%> (ø)
...b/detekt/metrics/processors/ProjectLOCProcessor.kt	100.00% <0.00%> (ø)
...detekt/metrics/processors/PackageCountProcessor.kt	93.75% <0.00%> (ø)
...ain/kotlin/io/github/detekt/metrics/LinesOfCode.kt	95.45% <0.00%> (ø)
... and 470 more

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[mateot1]

sorry for the delay. I updated this to use a new config field and added a default to default-detekt-config.yml. let me know if there's anything I missed for adding a new config field.