build(frontend): make embedded assets the default behavior

[hsmatulis]

Inverts the build tag logic to ensure that standard go build commands produce self-contained binaries with embedded assets. The dev workflow allowing for live updates must be explicitly specified now.

[bwplotka]

This could be also verified with test: #1822

Also if we do this let's ensure https://github.com/GoogleCloudPlatform/prometheus-engine/blob/main/hack/update-ui.sh works, can you double check that?

[hsmatulis]

This could be also verified with test: #1822

Yup! thats awesome, I'll rebase it

Also if we do this let's ensure https://github.com/GoogleCloudPlatform/prometheus-engine/blob/main/hack/update-ui.sh works, can you double check that?

Hmm it looks like that script is already failing at head, and has been since this commi 3 years ago: 26581ba

Looks like we removed the static/.gitignore dir that touch static/.gitignorein the script expects

[bwplotka]

I think I would prefer to keep the current state of things.

• We have test now that ensures static resources: https://github.com/GoogleCloudPlatform/prometheus-engine/actions/runs/20150993494/job/57843507041?pr=1823
• It's inconsistent with upstream. I'd actually try to change upstream first, Prometheus has the same issue and they didn't change to embed being default AFAIK (maybe no one proposed this!)
• It's inconsistent with many release branches we have
• Feel this PR would likely make local dev harder but maybe I'm wrong 🤔

Perhaps more work vs benefits?