feat: changed request body schema name when using omitted/picked type

[JadenKim-dev]

PR Checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Other... Please describe:

What is the current behavior?

When using OmitType or PickType in the swagger.body configuration, the schema name become PickTypeClass or OmitTypeClass.

Issue Number: N/A

What is the new behavior?

It uses schema name which reflect crud method, table name, and source.
ex) 'create' route, 'base' table, request body -> CreateBaseBodyDto

Additionally, improved test code to validate exception message, and remove unnecessary null checks and optional chaining

Does this PR introduce a breaking change?

• Yes
• No

Other information