build: remove workspace-hack from proc-macro crates' dependencies

To avoid many dependencies compiled twice, once as normal dependency and once as build-dependency (including very heavy onces, like zstd, aws-sdk-s3).

**This reduces fresh debug build's compile time from >400s to <300s on my mac.**

I'm not 100% sure about the mechanism yet, but it's clear that feature selection and dependency selection work differently for build-dependencies (incl proc-macros). When `workspack-hack` is used as a proc-macro crate's dependency, all its dependencies *can be* compiled twice.

See #9553 (comment) for more details.

src/common/proc_macro/Cargo.toml

@@ -23,7 +23,5 @@ proc-macro2 = { version = "1", default-features = false }
 syn = "1"
 bae = "0.1.7"
 
-[target.'cfg(not(madsim))'.dependencies]
-workspace-hack = { path = "../../workspace-hack" }
 [lints]
 workspace = true

src/prost/helpers/Cargo.toml

@@ -11,9 +11,6 @@ proc-macro2 = { version = "1", default-features = false }
 quote = "1"
 syn = "2"
 
-[target.'cfg(not(madsim))'.dependencies]
-workspace-hack = { path = "../../workspace-hack" }
-
 [package.metadata.cargo-machete]
 ignored = ["workspace-hack"]