Deps: Update Bevy from 0.16 to to 0.17.

[kpreid]

Note that this, unfortunately, adds a dependency on getrandom 0.3 which requires configuring RUSTFLAGS for all-is-cubes-wasm. In principle, having done this configuration means we could roll back 50bcfbfea6473bfa7bdce9892570dd846a3d26c1 which made all-is-cubes-wasm carefully avoid getrandom, but this is not the time for that.

[kpreid]

Lint jobs are failing because RUSTFLAGS=-Dwarnings in the environment overrides build.rustflags in .cargo/config.toml. I am still thinking about what to do about this. Some possibilities:

• have xtask take a --deny-warnings argument, read the Cargo config, and merge these values
• have xtask read RUSTFLAGS, read the Cargo config, and merge these values
• skip denying warnings (unset RUSTFLAGS) when building wasm (bad, but easier to implement)
• have xtask edit the config files to insert -Dwarnings into the build.rustflags value (this has the advantage that it doesn't need to adjust the environment for each individual build command based on directory)

I have also filed an issue with Bevy about removing this getrandom dep which isn't actually used in this part of the code: https://github.com/bevyengine/bevy/issues/21336