Changes

fix(prow-jobs): update TARGET to release-9.0-beta.2 in monitoring periodics (#3650)

This pull request updates the
`prow-jobs/pingcap/monitoring/periodics.yaml` file to use a more recent
version of the Go programming language and updates a branch name in the
environment configuration. These changes ensure the periodic jobs are
using the latest stable tools and correct target branches.

### Updates to Go image versions:
* Updated the Go image from `golang:1.23.2` to `golang:1.23.11` in three
different periodic job configurations to ensure compatibility with the
latest patches and improvements.
[[1]](diffhunk://#diff-42023fd3a034e5c540da3b9f7b6982f48acb7ee3545326f91f6abfb65cd92d4dL17-R17)
[[2]](diffhunk://#diff-42023fd3a034e5c540da3b9f7b6982f48acb7ee3545326f91f6abfb65cd92d4dL136-R136)
* Updated the Go image from `golang:1.23` to `golang:1.23.11` in another
periodic job configuration.

### Environment configuration update:
* Changed the `TARGET` environment variable value from
`release-9.0-beta.1` to `release-9.0-beta.2` to reflect the updated
branch name.
 (commit: 8fc90fe)