PR #25431 - OpenAPITools/openapi-generator

Drop locals the process*TypeProperty methods compute but never read.
Move the column prologue copied into all seven process*TypeProperty methods (column and table names, the x-postgresql-schema skip, the snake_case comment, the vendor-extension maps) into one private startColumn helper. Call order, log messages and public signatures are unchanged.

PostgreSQL: @iri

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Run the following to build the project and update samples:
```
./mvnw clean package || exit
./bin/generate-samples.sh ./bin/configs/*.yaml || exit
./bin/utils/export_docs_generators.sh || exit
```
(For Windows users, please run the script in WSL)
Commit all changed files.
This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
These must match the expectations made by your contribution.
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#25431 Refactor of `PostgresqlSchemaCodegen`; generated output is unchanged