fix(sfs): name the update operation in the update diagnostics

[devpie]

Description

Three diagnostics inside Update paths were copied from Create and still report a creation failure. #1740 corrected the resource pool's update wait; this covers what is left of the same copy-paste in the SFS service:

• sfs/resourcepool: the missing-ID guard right above the line feat(sfs): make resource pool wait timeouts configurable #1740 corrected
• sfs/share: the same guard, and the diagnostic of the update wait

Only the summaries change. The details are left alone on purpose: UpdateShareWaitHandler polls GetShare until the share reaches created, and a share has no updating state (sfs@v0.11.2 documents pending, creating, created, error, deleting), so after a PATCH the first poll normally returns right away. share get describes that better than a wait would.

Text only, no behaviour change. There is no issue for this; the wording was noticed while working on #1740.

Checklist

• Issue was linked above — no issue exists; happy to open one if you prefer
• Code format was applied: make fmt
• Examples were added / adjusted (see examples/ directory) — not applicable, no schema change
• Docs are up-to-date: make generate-docs (will be checked by CI)
• Unit tests got implemented or updated — not applicable: no test asserts these strings, and the existing ExpectError patterns cover the create paths
• Acceptance tests got implemented or updated — not applicable for a diagnostic string
• Unit tests are passing: make test (will be checked by CI)
• No linter issues: make lint (will be checked by CI)