Cherry-pick from oracle-structsupport

[vanshikaagupta22]

• cherry-pick Provide Struct data type support for oracle plugin #659

• update to 1.11.15-SNAPSHOT version

[gemini-code-assist]

Code Review

This pull request introduces support for Oracle STRUCT (User-Defined Types) in the Oracle database plugin, enabling the mapping of structured database types to CDAP StructuredRecord schemas and records. It implements schema reading, attribute mapping, and data conversion for nested structures and Oracle-specific types, along with comprehensive unit tests. The review feedback identifies several critical robustness and performance issues, including potential NullPointerException risks when retrieving connections from result set statements or loading classes via the bootstrap classloader, SQL query ambiguity when extracting type owners, missing validation for null type owners, and performance bottlenecks from repeated reflection calls.