[IR] Fix mangling generic properties from IR-based descriptors

For type parameters of generic properties,
`DeclarationDescriptor#getContainingDeclaration` must return
the property descriptor instead of the accessor function descriptor.

^KT-57436 Fixed

compiler/testData/ir/irText/expressions/variableAsFunctionCallWithGenerics.kt

@@ -1,6 +1,7 @@
 // FIR_IDENTICAL
-// MUTE_SIGNATURE_COMPARISON_K2: ANY
-// ^ KT-57429
+
+// MUTE_SIGNATURE_COMPARISON_K2: JS_IR
+// ^ KT-57818
 
 val <T : CharSequence> T.gk: () -> T
     get() = { -> this }