Fix OpenSearch service and search URL construction

[kshepherd]

References

• Requires Backend DSpace PR Fix OpenSearch base URL and remove unused configs DSpace#12700

Description

OpenSearch service URLs in DSpace 7.0 - 10.0 are broken, because they are prefixed with the full opensearch/search path instead of just opensearch/. This PR along with the related PR ensure that correct service and search URLs are constructed.

Instructions for Reviewers

Note to reviewers re: failing unit tests - these failures are due to the fact that the main branch currently has /opensearch/search set as the svccontext value, so search URLs end up as /opensearch/search/search in current tests. Once DSpace/DSpace#12700 is merged, these tests will pass.

Changes:

• Update rss.component.ts so that the websvc.opensearch.svccontext is treated as a true base path (matching the controller mapping)
• Change updateRssLinks() method so that it appends /search to the search URLs and /service to the service URL as appropriate

To Test:

Test instructions are the same as the backend PR: DSpace/DSpace#12700

• My PR is created against the main branch of code (unless it is a backport or is fixing an issue specific to an older branch).
• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes ESLint validation using npm run lint
• My PR doesn't introduce circular dependencies (verified via npm run check-circ-deps)
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• My PR includes details on how to test it. I've provided clear instructions to reviewers on how to successfully test this fix or feature.

[tdonohue]

👍 Thanks @kshepherd ! I tested this alongside the backend PR (DSpace/DSpace#12700) and verified that they fix the OpenSearch issues and that RSS feeds still work properly.

This PR however needs to wait to be merged until the backend is ready to merge. See my comments on the backend PR.