spl: fix metadata feature failing to build standalone

[plutohan]

Fixes #3291.

cargo build -p anchor-spl --no-default-features --features metadata fails because metadata.rs uses spl_token_interface::ID and spl_associated_token_account_interface::program::ID, which are only pulled in by the token/associated_token features. This enables those two (already optional) crates from the metadata feature so it builds standalone. No code changes.

Verified --features metadata builds and the default build is unchanged.

@acheroncrypto you suggested using the lighter spl-associated-token-account-client instead. I went with the existing interface crates since it's a one-line change with no new deps, but can switch to the client crates if you'd prefer.

[vercel]

@plutohan is attempting to deploy a commit to the OtterSec Team on Vercel.

A member of the Team first needs to authorize it.

[jamie-osec]

Please use the suggested fix with spl-associated-token-account-client; it makes our dep tree lighter

[jamie-osec]

This is currently applied inconsistently in the codebase, but please use dep:<crate> syntax for new feature-dependencies as it makes them a little clearer.

[plutohan]

Done. I switched these to dep:, and also flipped token/associated_token to dep: since using dep: for those crates drops their implicit feature, which the bare references relied on.