Fix multiple allocations of empty PersistentMap in PersistentSetMultimap

The `persistentMapOf` overload without arguments should be used there.

The needed overload is not available in the version of `kotlinx.immmutable 0.3.2`,
so the library is updated to the latest version.

This commit also removes the dependency on the `kotlinx-collections-immutable-metadata`
as it's not published anymore for new versions of `kotlinx-collections-immutable`.

^KT-64987 fixed

prepare/compiler/compiler.pro

@@ -317,6 +317,7 @@
 }
 -keepclassmembers class kotlinx.collections.immutable.ExtensionsKt {
     kotlinx.collections.immutable.PersistentMap toPersistentHashMap(java.util.Map);
+    kotlinx.collections.immutable.PersistentMap persistentHashMapOf(kotlin.Pair[]);
     kotlinx.collections.immutable.PersistentSet persistentHashSetOf(java.lang.Object[]);
 }
 -keepclassmembers class com.intellij.lang.jvm.JvmParameter {