Backport of [NET-11150] ci: fix conditional skip and add safeguard into release/1.1.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #637 to be assessed for backporting due to the inclusion of the label backport/1.1.

🚨

Warning automatic cherry-pick of commits failed. If the first commit failed,
you will see a blank no-op commit below. If at least one commit succeeded, you
will see the cherry-picked commits up to, not including, the commit where
the merge conflict occurred.

The person who merged in the original PR is:
@zalimeni
This person should manually cherry-pick the original PR into a new backport PR,
and close this one when the manual backport PR is merged in.

merge conflict error: POST https://api.github.com/repos/hashicorp/consul-dataplane/merges: 409 Merge conflict []

The below text is copied from the body of the original PR.

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Fix CI skip workflow by adopting tj-actions/changed-files (used by several other hashicorp repos) and putting in safeguards to avoid false negatives on changed files due to inappropriate workflow triggers.

Reproduced bug (skipped checks on Dockerfile change): https://github.com/hashicorp/consul-dataplane/actions/runs/10984338025/job/30494819791?pr=630#step:3:14

Debugging 🧵 for posterity, which has some notes w/ more background on our previous script and potential gotchas: https://go.hashi.co/net-11150-debugging-slack

PRs for other repos:

• [NET-11150] ci: fix conditional skip and add safeguard consul#21781
• [NET-11150] ci: fix conditional skip and add safeguard consul-k8s#4363

Testing

pull_request retrieves changes between base and feature branch: https://github.com/hashicorp/consul-dataplane/actions/runs/11017376755/job/30595124657?pr=637#step:4:64

Prints both skippable and non-skippable files: https://github.com/hashicorp/consul-dataplane/actions/runs/11017376755/job/30595124657?pr=637#step:5:12

Skip test: https://github.com/hashicorp/consul-dataplane/actions/runs/11018306352/job/30598259268?pr=638#step:6:6

Safeguard test: https://github.com/hashicorp/consul-dataplane/actions/runs/11016637261/job/30592629656?pr=636#step:2:14

Simulated push with non-skippable commit (diff is just latest commit): https://github.com/hashicorp/consul-dataplane/actions/runs/11020606567/job/30605759628#step:3:62

Simulated push with skippable commit (diff is just latest commit): https://github.com/hashicorp/consul-dataplane/actions/runs/11020613882/job/30605785364#step:4:12

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Overview of commits

• b13c5cd

[hashicorp-cla-app]

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