Update Ironbank Dockerfile to ubi 9.4

[jlind23]

Change ubi base image from 9.3 to 9.4 used in Ironbank Docker images for all 8.X Beats

[mergify[bot]]

This pull request does not have a backport label. If this is a bug or security fix, could you label this PR @jlind23? 🙏. For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed branches, such as:

• backport-v8./d.0 is the label to automatically backport to the 8./d branch. /d is the digit

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[jlind23]

@pierrehilbert looks like the doc build worked but the status is not reported in this PR check - https://buildkite.com/elastic/docs-build-pr/builds/98467 how can we solve this?

[pierrehilbert]

run docs-build