Is your feature request related to a problem? Please describe.
The 1Password SDK has very small API limits for personal and family accounts. The external-secrets provider does implement caching, but it does not update the externalsecret_provider_api_calls_count metric to help tune the cache.

Describe the solution you'd like
Add calls to metrics.ObserveAPICall in the 1Password SDK provider where appropriate. As a bonus, introduce new metrics for cache performance (average/min/max cache entry age, cache population size, and/or cache pressure or cache eviction rate).

Describe alternatives you've considered
Scrape logs, observe the secret store status, manual tuning.

Additional context
See #4925 for cache discussion.