Allow unwrap() in tests when clippy::unwrap_used is denied (#11616)

## Problem

The proxy denies using `unwrap()`s in regular code, but we want to use
it in test code
and so have to allow it for each test block.

## Summary of changes

Set `allow-unwrap-in-tests = true` in clippy.toml and remove all
exceptions.

proxy/src/auth/backend/jwt.rs

@@ -776,7 +776,6 @@ impl From<&jose_jwk::Key> for KeyType {
 }
 
 #[cfg(test)]
-#[expect(clippy::unwrap_used)]
 mod tests {
     use std::future::IntoFuture;
     use std::net::SocketAddr;

proxy/src/auth/credentials.rs

@@ -253,7 +253,6 @@ fn project_name_valid(name: &str) -> bool {
 }
 
 #[cfg(test)]
-#[expect(clippy::unwrap_used)]
 mod tests {
     use ComputeUserInfoParseError::*;
     use serde_json::json;