[8.12] [Fleet] Fix get file handler for bundled package (#172182) (#1…

…73058) (#173911)

# Backport

This will backport the following commits from `main` to `8.12`:
- [[Fleet] Fix get file handler for bundled package (#172182)
(#173058)](#173058)

<!--- Backport version: 8.9.8 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Nicolas
Chaulet","email":"[email protected]"},"sourceCommit":{"committedDate":"2023-12-12T16:05:46Z","message":"[Fleet]
Fix get file handler for bundled package (#172182)
(#173058)","sha":"fa3b6f4c9da88e6ddbd1fae7c502d00353c55134","branchLabelMapping":{"^v8.13.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","Team:Fleet","backport:prev-minor","v8.13.0"],"number":173058,"url":"https://github.com/elastic/kibana/pull/173058","mergeCommit":{"message":"[Fleet]
Fix get file handler for bundled package (#172182)
(#173058)","sha":"fa3b6f4c9da88e6ddbd1fae7c502d00353c55134"}},"sourceBranch":"main","suggestedTargetBranches":[],"targetPullRequestStates":[{"branch":"main","label":"v8.13.0","labelRegex":"^v8.13.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/173058","number":173058,"mergeCommit":{"message":"[Fleet]
Fix get file handler for bundled package (#172182)
(#173058)","sha":"fa3b6f4c9da88e6ddbd1fae7c502d00353c55134"}}]}]
BACKPORT-->