[clang-tools-extra] [clang-tidy][NFC] Fix `bugprone-unchecked-optional-access` warnings in codebase (PR #170004)

[Victor Chernyakin via cfe-commits]

================
@@ -225,10 +225,12 @@ void FunctionSizeCheck::check(const MatchFinder::MatchResult &Result) {
         << ActualNumberParameters << ParameterThreshold.value();
   }
 
-  for (const auto &CSPos : FI.NestingThresholders) {
-    diag(CSPos, "nesting level %0 starts here (threshold %1)",
-         DiagnosticIDs::Note)
-        << NestingThreshold.value() + 1 << NestingThreshold.value();
+  if (NestingThreshold) {
+    for (const auto &CSPos : FI.NestingThresholders) {
+      diag(CSPos, "nesting level %0 starts here (threshold %1)",
+           DiagnosticIDs::Note)
+          << NestingThreshold.value() + 1 << NestingThreshold.value();
----------------
localspook wrote:

For consistency with the rest of the code, and to assert that we really do expect the optional to be engaged:
```suggestion
          << *NestingThreshold + 1 << *NestingThreshold;
```

https://github.com/llvm/llvm-project/pull/170004