Bump Elasticsearch in CI to 7.10.1

What does this MR do?

We are planning on upgrading our production environment to 7.10.2 so we want to use the same version in CI.

There isn't, yet, a 7.10.2 published to dockerhub. Elastic also has their own registry where they released 7.10.2 but we've had problems with being rate limited from this registry before !21750 (merged) so it's best to just go with 7.10.1 in CI for now until it's published.

I did, however, confirm in CI that 7.10.2 does work with the Elastic docker image 5597a647 .

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team