[FIR] Drop an obsolete TODO

In K2 we have `EXPLICIT_TYPE_ARGUMENTS_IN_PROPERTY_ACCESS`
and `EXPRESSION_OF_NULLABLE_TYPE_IN_CLASS_LITERAL_LHS`
which seem to cover the same use cases as
`RESERVED_SYNTAX_IN_CALLABLE_REFERENCE_LHS` used to
(at least it seems so, based on the source code of
`resolveReservedExpressionSyntaxOnDoubleColonLHS()`).

^KT-59835 Obsolete

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirClassLiteralChecker.kt

@@ -74,7 +74,6 @@ object FirClassLiteralChecker : FirGetClassCallChecker() {
         }
 
         if (argument !is FirResolvedQualifier) return
-        // TODO, KT-59835: differentiate RESERVED_SYNTAX_IN_CALLABLE_REFERENCE_LHS
         if (argument.typeArguments.isNotEmpty() && !resolvedFullyExpandedType.isAllowedInClassLiteral(context)) {
             val symbol = argument.symbol
             symbol?.lazyResolveToPhase(FirResolvePhase.TYPES)