test: Modernise TestFleetAutoScalerRollingUpdate e2e tests

[markmandel]

What type of PR is this?

Uncomment only one /kind <> line, press enter to put that in a new line, and remove leading whitespace from that line:

/kind breaking
/kind bug

/kind cleanup

/kind documentation
/kind feature
/kind hotfix
/kind release

What this PR does / Why we need it:

Cleans up the test to have a more modern approach, but also avoids panics now if autopilot shuts down a node mid test, allowing a retry

Which issue(s) this PR fixes:

N/A

Did you use AI tools in preparing this PR?:

N

Special notes for your reviewer:

flakes in #4629

[agones-bot]

Build Succeeded 🥳

Build Id: 49933321-1737-474c-8c2b-d379972aa2e9

The following development artifacts have been built, and will exist for the next 30 days:

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.59.0-dev-f76bede
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.59.0-dev-f76bede
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.59.0-dev-f76bede-linux
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.59.0-dev-f76bede
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.59.0-dev-f76bede
• image: us-docker.pkg.dev/agones-images/ci/agones-processor:1.59.0-dev-f76bede
• Linux C++ SDK (build): agonessdk-1.59.0-dev-f76bede-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.59.0-dev-f76bede.zip

A preview of the website (the last 30 builds are retained):

• https://f76bede-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/googleforgames/agones.git pull/4631/head:pr_4631 && git checkout pr_4631
helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.59.0-dev-f76bede

[agones-bot]

Build Succeeded 🥳

Build Id: 22ba36d2-cb93-4ec3-a2eb-6a33d31275f1

The following development artifacts have been built, and will exist for the next 30 days:

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.59.0-dev-c4bb042
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.59.0-dev-c4bb042
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.59.0-dev-c4bb042-linux
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.59.0-dev-c4bb042
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.59.0-dev-c4bb042
• image: us-docker.pkg.dev/agones-images/ci/agones-processor:1.59.0-dev-c4bb042
• Linux C++ SDK (build): agonessdk-1.59.0-dev-c4bb042-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.59.0-dev-c4bb042.zip

A preview of the website (the last 30 builds are retained):

• https://c4bb042-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/googleforgames/agones.git pull/4631/head:pr_4631 && git checkout pr_4631
helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.59.0-dev-c4bb042