tbv2: fix type names for std::optional

[JakeHillion]

tbv2: fix type names for std::optional

Type names of optional elements were accidentally left as todo. Update std::optional to use make_field and correctly name its elements.

Test Plan:

• CI
• Updated the integration tests to test the names.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (71e734b) 62.27% compared to head (bb724f4) 62.27%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #449 +/- ## ======================================= Coverage 62.27% 62.27% ======================================= Files 123 123 Lines 11975 11975 Branches 1953 1953 ======================================= Hits 7458 7458 Misses 3573 3573 Partials 944 944 ```

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