refactor: improved logic for ignoring endpoints

[aryamohanan]

Refactored the implementation of ignored endpoints by moving the filtering logic to startSpan. This change makes it easier to extend in the future, simplifies modification, and resolves the issue with accessing the current span for ignored span.

Tasks

• - Refactor the existing span filter logic within the startSpan function.
• - Get the ignore endpoints config in cls
• - Perform the span mapping within the span buffer while adding a span.

Pending

• - Apply filtering based on operation as well as endpoints refactor: updated the filter logic to filter array of operations #1580.
• - An integration test for the ignore endpoint (New PR)

[aryamohanan]

We need the agent config available at the cls.