[docs] Fix OpenAPI 3 validation errors in rest catalog spec

[ArnavBalyan]

Purpose

• The rest catalog OpenAPI spec at docs/static/rest-catalog-open-api.yaml is not OpenAPI 3 compliant has 32 errors. Swagger UI allows this, but openapi-generator-cli fails on this.
• Several named ErrorResponse components have schema.$ref pointing to another response object instead of a schema. The databaseNamePattern parameter is declared in: path but is a sql like filter, so it has to be in: query.
• Fixes: [Bug] OpenApi generation fails with errors #7760

Tests

• Validated locally with openapi-generator-cli 7.22.0. Before the change the same command reports 32 errors.