fix(zellij-server): unblock building on 32bit targets

[tranzystorekk]

After the migration to wasmi (#4449), we should be able to build for 32bit targets (wasm runtimes have notoriously had issues with such targets, see https://docs.wasmtime.dev/stability-tiers.html#unsupported-features-and-platforms).

While testing with builds on Void Linux for i686, I noticed the static asserts in our code that hardcode support for 64bit platforms only. These were introduced as an optimization (#3043), but I'd argue that this is a bit overly pedantic, especially when it effectively limits possible target platforms for no reason.

Hence, my proposal to drop them altogether as a simple solution. I'm aware that we could instead rewrite those to take platform-specific pointer size into account, but especially in the case of TerminalCharacter it becomes cumbersome to cleanly express what the expected size should be.

When testing I at least made sure that the new reported size only goes down for the affected target.

cc @aidanhs for comments and suggestions

[imsnif]

@aidanhs - if you're around, available, willing and have the time to help us out by giving some input on this - it would be much appreciated!