Stop trimming trailing slashes from MCP server URLs on save. Some MCP
servers (e.g. Bitrix24) require a trailing slash; removing it triggers a
301 redirect that drops Authorization headers, resulting in 400 errors.
The trailing-slash trim is now skipped when the connection type is 'mcp',
while OpenAPI connections continue to have it stripped as before.
Fixes open-webui#21179
In opensearch-py >= 3.0.0, IndicesClient.refresh() no longer accepts the
index name as a positional argument. This causes a TypeError when
uploading documents to knowledge bases with OpenSearch backend.
Changes positional arguments to keyword arguments (index=...) in all
three refresh() calls in the OpenSearch vector DB client.
Fixes#20649