fix: corrected the pagination counts for vendor search

[devlopharsh]

Fixes: #4039

Issue: #4039

Summary

The problem was that filtered vendor results were returned correctly, but
PaginationData.totalRowCount was derived from the full CouchDB view size
instead of the filtered subset. As a result, the API could return a single
matching vendor while still reporting larger totalElements and totalPages,
which also produced incorrect next and last pagination links.

Changes Made

• Update shared pagination count handling in
  libraries/datahandler/.../DatabaseRepositoryCloudantClient.java
• Detect filtered view queries (key, keys, startKey, endKey)
• Compute totalRowCount from the filtered query result instead of using the
  full view totalRows
• Add regression assertions in
  backend/vendors/.../VendorHandlerTest.java to verify filtered search counts

Suggest Reviewer

@deo002

How To Test?

1. Run the existing REST-side vendor tests:
   • mvn -q test -pl rest/resource-server '-Dtest=VendorTest' '-Dbase.deploy.dir=.'
   • mvn -q test -pl rest/resource-server '-Dtest=VendorSpecTest' '-Dbase.deploy.dir=.'
2. manual verification against a running server by the command GET /resource/api/vendors?page=0&page_entries=10&searchText=<matching-text>

Checklist

Must:

• All related issues are referenced in commit messages and in PR
• No new dependencies were added
• Relevant tests were run locally where environment allowed
• If code is AI-generated, mention the tool and model used

[devlopharsh]

@deo002 , Hello sir ,
please have a review over the PR and acknowledge me for any further changes needed , thank you .