K2: Use correct position for substitution constrains in builder inference

Before, we were wrapping the original constraint position into
ConeBuilderInferenceSubstitutionConstraintPosition twice during the
constraint substitution in builder inference.

It was causing problems with diagnostic reporting.

Remove TODOs about diagnostic reporting from FirBuilderInferenceSession.
Propagation of errors from the common system is now implemented
Diagnostic reporting in updateCalls isn't needed, since we
report errors after the system completion unlike K1

Relates to KT-53749

compiler/testData/diagnostics/tests/inference/builderInference/constraints/violating.fir.kt

@@ -13,7 +13,7 @@ fun main() {
             override fun foo(): MutableList<String> = <!RETURN_TYPE_MISMATCH!>this@buildList<!>
         }
     }
-    <!NEW_INFERENCE_ERROR!>buildList {
+    <!TYPE_MISMATCH!>buildList {
         add(3)
         val x: String = <!INITIALIZER_TYPE_MISMATCH!>get(0)<!>
     }<!>
@@ -26,7 +26,7 @@ fun main() {
         add(y)
         val x: MutableList<String> = <!INITIALIZER_TYPE_MISMATCH!>this@buildList<!>
     }
-    <!NEW_INFERENCE_ERROR!>buildList {
+    <!TYPE_MISMATCH!>buildList {
         add("")
         val x: StringBuilder = <!INITIALIZER_TYPE_MISMATCH!>get(0)<!>
     }<!>