[Discover] Fix flaky chart interval test

[jughosta]

Closes #146223

https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/1610

[jughosta]

Closing in favor of #146667 for 8.6 only

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 02e619b

Metrics [docs]

Unknown metric groups

ESLint disabled in files

id	before	after	diff
osquery	1	2	+1

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	19	21	+2
fleet	59	65	+6
osquery	109	115	+6
securitySolution	442	448	+6
total			+20

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	20	22	+2
fleet	68	74	+6
osquery	110	117	+7
securitySolution	519	525	+6
total			+21

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

cc @jughosta