Revert "git: Intercept signing prompt from GPG when committing" (#34306)

Reverts zed-industries/zed#34096

This introduced a regression, because the unlocked key can't benefit
from caching.

Release Notes:
- N/A

crates/git/Cargo.toml

@@ -41,9 +41,9 @@ futures.workspace = true
 workspace-hack.workspace = true
 
 [dev-dependencies]
-gpui = { workspace = true, features = ["test-support"] }
 pretty_assertions.workspace = true
 serde_json.workspace = true
-tempfile.workspace = true
 text = { workspace = true, features = ["test-support"] }
 unindent.workspace = true
+gpui = { workspace = true, features = ["test-support"] }
+tempfile.workspace = true