CI: Remove the aarch64 appimage build steps from release

[the-mikedavis]

The steps mistakenly produce a x86_64 appimage and call it aarch64. linuxdeploy doesn't currently support producing aarch64 appimages so we should just remove these steps for aarch64-linux.

Closes #5237

[gabydd]

for anyone confused like I was, the ci is failing because GITHUB_REF_NAME becomes 7832/merge(see github/docs#15319) which has a slash in it so we refer to an uncreated directory which doesn't happen in the normal release process

[agatekartik]

Appears there is a aarch64 now https://github.com/linuxdeploy/linuxdeploy/releases/download/1-alpha-20240109-1/linuxdeploy-aarch64.AppImage - will we see a corresponding helix AppImage soon?

[the-mikedavis]

Feel free to submit a PR! (Once a linuxdeploy version with aarch64 support is released)

[agatekartik]

Feel free to submit a PR! (Once a linuxdeploy version with aarch64 support is released)

Thank you - yes might be a good idea, I tried a few things off the cuff (like undoing this commit and then ensuring aarch64 was used to create appimage) - however, from the runner output, looks like the binaries are not of the correct format - which means, while the linuxdeploy tool maybe aarch64, the binaries produced by the build are likely not (note: I haven't done a deep dive yet).
I shall fork and try locally with self hosted runners as time permits and see how to get things done, if they are indeed possible :-)

[agatekartik]

I tried getting the linuxdeploy-aarch64 tool to run on my raspberry pi 4. However, I keep getting a file format error of the linuxdeploy binary too. I guess it is best we remain patient till linuxdeploy announces release for aarch64