PayerDataExchange: Add server-side search and status filtering to getPdexDataRequests API

Summary

The PayerDataExchange page (apps/payer-admin-app/src/pages/PayerDataExchange.tsx) currently fetches a single page of results from getPdexDataRequests(ITEMS_PER_PAGE, offset) and applies searchQuery and selectedStatuses filters client-side. This causes a mismatch where totalCount and pagination reflect the unfiltered result set, potentially hiding real matches on other pages and showing a misleading "No requests found" state.

Expected Behaviour

• getPdexDataRequests should accept searchQuery and selectedStatuses (or equivalent) as query parameters.
• The API response's count should reflect the filtered total so that pagination is accurate.
• The PayerDataExchange component should pass searchQuery and selectedStatuses into getPdexDataRequests and remove local filtering logic.

Steps to Reproduce / Context

1. Open the Payer Data Exchange page with more than one page of data.
2. Enter a search term or select a status filter.
3. Only the currently fetched page is filtered; items on other pages that match are not shown.

Acceptance Criteria

• getPdexDataRequests API (backend) supports search and status query parameters.
• getPdexDataRequests TypeScript client in apps/payer-admin-app/src/api/pdex.ts passes those parameters to the API.
• PayerDataExchange passes searchQuery and selectedStatuses to getPdexDataRequests.
• totalCount is updated from the filtered API response so pagination is accurate.
• Local client-side filtering in PayerDataExchange is removed once API filtering is available.

References

• PR: https://github.com/wso2/reference-implementation-cms0057f/pull/269
• Review comment: https://github.com/wso2/reference-implementation-cms0057f/pull/269#discussion_r2973132201
• Requested by: @joelsathi

Review PR 269 and its discussion first, then inspect apps/payer-admin-app/src/api/pdex.ts and apps/payer-admin-app/src/pages/PayerDataExchange.tsx. Trace the backend getPdexDataRequests entry point and verify that search, status, filtered count, pagination, and removal of local filtering are covered by the acceptance criteria.