[7.x] [Fleet][EPM] Revert es-storage-related commits (#85942)

[jfsiii]

Backports the following commits to 7.x:

• [Fleet][EPM] Revert es-storage-related commits ([Fleet][EPM] Revert es-storage-related commits #85942)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 7a39887

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
triggersActionsUi	1.5MB	1.4MB	-26.9KB

Distributable file count

id	before	after	diff
default	47491	48249	+758

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
fleet	376.5KB	376.2KB	-311.0B
triggersActionsUi	161.5KB	161.6KB	+102.0B
total			-209.0B

Saved Objects .kibana field count

Every field in each saved object type adds overhead to Elasticsearch. Kibana needs to keep the total field count below Elasticsearch's default limit of 1000 fields. Only specify field mappings for the fields you wish to search on or query. See https://www.elastic.co/guide/en/kibana/master/development-plugin-saved-objects.html#_mappings

id	before	after	diff
epm-packages	18	15	-3
epm-packages-assets	8	-	-8
total			-11

Unknown metric groups

async chunk count

id	before	after	diff
triggersActionsUi	31	32	+1

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream