[7.14] [Cases] Fix connector's icon bug (#107633)

[cnasikas]

Backports the following commits to 7.14:

• [Cases] Fix connector's icon bug ([Cases] Fix connector's icon bug #107633)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 536ea81
• Storybooks Preview

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
cases	529.1KB	579.5KB	+50.4KB

Page load bundle

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

id	before	after	diff
cases	130.3KB	130.2KB	-66.0B

Unknown metric groups

async chunk count

id	before	after	diff
cases	15	14	-1

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