Remove all x86_64 mentions from iOS CI and build scripts

[mojganii]

This PR removes all references to the x86_64 architecture from the iOS CI pipeline and build scripts.

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This change is 

[linear]

IOS-797 Remove all x86_64 mentions from iOS CI and build scripts

[buggmagnet]

Reviewable status: 0 of 3 files reviewed, 1 unresolved discussion (waiting on @mojganii)

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ios/BuildInstructions.md line 15 at r1 (raw file):

rustup target install aarch64-apple-ios aarch64-apple-ios-sim

You only need to install the ARM simulator target, which matches the current Apple Silicon (M1/M2) architecture.

We can remove the (M1/M2) part, Apple Silicon is already the official name of this technology

[mojganii]

Reviewable status: 0 of 3 files reviewed, 1 unresolved discussion (waiting on @buggmagnet)

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ios/BuildInstructions.md line 15 at r1 (raw file):

Previously, buggmagnet wrote…

We can remove the (M1/M2) part, Apple Silicon is already the official name of this technology

Done.

[buggmagnet]

Reviewed 1 of 3 files at r1, 1 of 1 files at r2, 1 of 1 files at r3, all commit messages.
Reviewable status: 3 of 4 files reviewed, all discussions resolved

[github-actions]

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