[ci/cypress] Use spot instances

[jbudz]

This migrates the remaining ci-group-6 steps to n2-4-spot.

[elasticmachine]

Pinging @elastic/kibana-operations (Team:Operations)

[jbudz]

I'll ping all related teams with an FYI prior to merging in case issues come up.

[tylersmalley]

ci-group-6 is a n2-custom-6-16384. Looks like the tests complete with a reduced CPU, so we should be good but something to keep in mind.

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: c212c54

Failed CI Steps

• APM Cypress Tests

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	60	66	+6
osquery	109	115	+6
securitySolution	445	451	+6
total			+20

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	20	22	+2
fleet	69	75	+6
osquery	110	117	+7
securitySolution	521	527	+6
total			+21

History

• 💔 Build #93854 failed 3437928
• 💔 Build #93724 failed f4babb2
• 💛 Build #93339 was flaky 733da0b

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