Search function not returning entries when they are in an inactive shard

[lkatalin]

Description
When using rekor-cli search --sha <sha>, only entries from the current active shard are returned, and those in inactive shards are ignored. This is confusing and also not desirable as it returns incomplete data.

For example, rekor-cli get --log-index 0 returns an entry with sha 45c7b11fcbf07dec1694adecd8c5b85770a12a6c8dfdcf2580a2db0c47c31779 and UUID 362f8ecba72f4326b08416d417acdb0610d4a030d8f697f9d0a718024681a00fa0b9ba67072a38b5. However, searching for this sha does not return an entry with that UUID as it only returns entries in the current shard:

$ rekor-cli search --sha 45c7b11fcbf07dec1694adecd8c5b85770a12a6c8dfdcf2580a2db0c47c31779
Found matching entries (listed by UUID):
24296fb24b8ad77ad2f305428d7c222d7b77f56453dd4b6e6851752ecacc78e5992779c8f9b61dd9
24296fb24b8ad77aa41106ebaa4966010c03def6a04257d5319f5b7938cf677a932ee0126265a479

Proposed solution: change search functionality to search inactive shards as well as active shard.

Slack conversation reference: https://sigstore.slack.com/archives/C01CX4E2K70/p1699468367456719

[bobcallaway]

nothing in the index fetch code appears to be shard-aware, so i'm suspect of the backfill script at the moment.