fix: commit request queue dedup cache only after batch_add_requests succeeds

[vdusek]

Both Apify request queue clients (ApifyRequestQueueSingleClient, ApifyRequestQueueSharedClient) inserted new requests into their local _requests_cache (and the single client's _head_requests) before calling batch_add_requests. When that API call failed, the poisoned cache entries caused a subsequent user retry of the same request to be deduplicated locally and never re-sent to the platform — silent request loss.

The cache/head commit now happens after batch_add_requests succeeds, committing only the requests the platform actually accepted (entries in unprocessed_requests are skipped). The previous "remove unprocessed from cache" cleanup loops are absorbed into this skip, since those ids are simply never added now.

Crawlee already deduplicates a batch by unique_key (via _transform_requests) before it reaches these clients, so deferring the local cache write does not lose meaningful within-batch deduplication.

Added a parametrized regression test covering both clients: a failed batch_add_requests leaves no cached entry, and the retry reaches the platform.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.98%. Comparing base (0daca28) to head (710ecbe).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #975      +/-   ##
==========================================
+ Coverage   89.90%   89.98%   +0.07%     
==========================================
  Files          49       49              
  Lines        3091     3105      +14     
==========================================
+ Hits         2779     2794      +15     
+ Misses        312      311       -1     

Flag	Coverage Δ
e2e	35.78% <6.25%> (-0.13%)	⬇️
integration	56.74% <31.25%> (-0.13%)	⬇️
unit	81.09% <100.00%> (+2.35%)	⬆️

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