[Cases] Guardrails: Limit bulk get cases and bulk get attachments

[adcoelho]

Connected to #146945

Summary

Description	Limit	Done?	Documented?
Total number of attachments returned by bulk get API	100	✅	No (internal)
Total number of cases returned by bulk get API	1000	✅	No (internal)

• Replaced the code validation with schema validation.
• BulkGet Cases
  • The minimum of cases that can be returned is now 1(was not validated before).
• BulkGet Attachments
  • The maximum of attachments that can be returned is now 100(was 10000).
  • The minimum of attachments that can be returned is now 1(was not validated before).
• Updated unit and e2e tests.
• The documentation was not updated because these are internal APIs.
• Skipping the release notes because these are internal APIs.

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)

[elasticmachine]

Pinging @elastic/response-ops-cases (Feature:Cases)

[js-jankisalvi]

looks good 👍 documentation is missing 😄

[adcoelho]

@js-jankisalvi internal apis dont need it ;D

[js-jankisalvi]

@js-jankisalvi internal apis dont need it ;D

Ahh great!! didn't know that 😄 Thanks

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 59d17a5

Failed CI Steps

• FTR Configs #6

Test Failures

• [job] [logs] FTR Configs #6 / discover/group3 discover request counts data view mode should send 2 requests (documents + chart) when adding a filter

Metrics [docs]

Page load bundle

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

id	before	after	diff
cases	144.5KB	144.6KB	+152.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	14	16	+2
securitySolution	410	414	+4
total			+6

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	15	17	+2
securitySolution	489	493	+4
total			+6

History

• 💔 Build #139935 failed 2cc4628
• 💚 Build #139844 succeeded 9d8aa19
• 💔 Build #139787 failed 4c6cebb
• 💔 Build #139778 failed 95fed99

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

cc @adcoelho