chore: testing fixes and cargo cleanup

This change makes sure all dependencies are now in the workspace-level
Cargo.toml.

Uses the `temp-env` crate to make the config tests less flaky.

Cargo.lock

@@ -214,6 +214,7 @@ dependencies = [
  "serde_json",
  "sha2",
  "task-local-extensions",
+ "temp-env",
  "thiserror",
  "tokio",
  "tracing",
@@ -2082,6 +2083,15 @@ dependencies = [
  "pin-utils",
 ]
 
+[[package]]
+name = "temp-env"
+version = "0.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96374855068f47402c3121c6eed88d29cb1de8f3ab27090e273e420bdabcf050"
+dependencies = [
+ "parking_lot",
+]
+
 [[package]]
 name = "termtree"
 version = "0.5.1"