FIR IDE: quickfix for WrapWithSafeLetCall

There is some behavior change regarding the new WrapWithSafeLetCall quickfix

1. it now works correctly on binary expressions by wrapping it with `()`
2. it now looks for a nullable position upward and do the modification there,
   if possible. For example, consider the following code

   ```
   fun bar(s: String): String = s

   fun test(s: String?) {
     bar(bar(bar(<caret>s)))
   }
   ```

   After applying this fix, FE1.0 yields

   ```
   bar(bar(s?.let { bar(it) }))
   ```

   while the new implementation yields

   ```
   s?.let { bar(bar(bar(it))) }
   ```

   This behavior aligns with FE1.0 if `bar` accepts nullable values.

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Arguments.kt

@@ -377,7 +377,7 @@ private fun checkApplicabilityForArgumentType(
 
         // Reaching here means argument types mismatch, and we want to record whether it's due to the nullability by checking a subtype
         // relation with nullable expected type.
-        val isMismatchDueToNullability = AbstractTypeChecker.isSubtypeOf(
+        val isMismatchDueToNullability = argumentType.canBeNull && !actualExpectedType.isNullable && AbstractTypeChecker.isSubtypeOf(
             context.session.typeContext,
             argumentType,
             actualExpectedType.withNullability(ConeNullability.NULLABLE, context.session.typeContext)

compiler/psi/src/org/jetbrains/kotlin/psi/psiUtil/ktPsiUtil.kt

@@ -347,6 +347,8 @@ fun PsiElement.parameterIndex(): Int {
     }
 }
 
+val KtValueArgument.argumentIndex: Int get() = (parent as KtValueArgumentList).arguments.indexOf(this)
+
 fun KtModifierListOwner.isPrivate(): Boolean = hasModifier(KtTokens.PRIVATE_KEYWORD)
 
 fun KtModifierListOwner.isProtected(): Boolean = hasModifier(KtTokens.PROTECTED_KEYWORD)