Flush metadata

[timbl]

This is designed to address https://github.com/linkeddata/rdflib.js/issues/441 along with other code to call updater.flagAuthorizationMetadata when the login state changes.

[bourgeoa]

@timbl can you review Angelo comments?

[bourgeoa]

After merging main, build succeed, but new tests fail :

update callback uri = undefined, ok = false, text = <<<Exception in update: Error: Update: Loaded <https://example.com/test/foo>but stil can't figure out what editing protcol it supports.
Error: Update: Loaded <https://example.com/test/foo>but stil can't figure out what editing protcol it supports.
  undefined
    Error: Update: Loaded <https://example.com/test/foo>but stil can't figure out what editing protcol it supports.  undefined
        at UpdateManager.update (/mnt/d/github/source/workspaces/rdflib/src/update-manager.ts:832:17)  undefined
        at /mnt/d/github/source/workspaces/rdflib/src/update-manager.ts:836:16  undefined
        at processTicksAndRejections (node:internal/process/task_queues:96:5)>>>

[angelo-v]

The failing tests are

• live-store-test.js
• update-manager-sparql-insert-test.ts