FIR2IR: Repeat the K1 behavior: SAM conversion with 'in' projection

It would be more consistently to prohibit the behavior from the unmuted
test (see KT-52428), but it was decided to postpone the breaking change.

Unfortunately, it didn't work to make a test where for computing
star projections we would need to substitute other type parameters
because effectively, it's not allowed to have SAM conversion when
star projections/wildcard is based on a type parameter which bounds
use other type parameters.

^KT-53552 In progress

compiler/backend-common/src/org/jetbrains/kotlin/backend/common/SamTypeFactory.kt

@@ -61,6 +61,8 @@ class SamTypeApproximator(builtIns: KotlinBuiltIns, languageVersionSettings: Lan
         return approximatedOriginalTypeToUse.removeExternalProjections(carefulApproximationOfContravariantProjection)
     }
 
+    // When changing this, please consider also changing the mirroring K2 function at
+    // org.jetbrains.kotlin.fir.backend.generators.AdapterGenerator.removeExternalProjections
     private fun KotlinType.removeExternalProjections(carefulApproximationOfContravariantProjection: Boolean): KotlinType? {
         val newArguments = arguments.mapIndexed { i, argument ->
             if (carefulApproximationOfContravariantProjection && argument.projectionKind == Variance.IN_VARIANCE) {