fix: Replace unwrap with proper error handling in set_domains handler (#4643)

Closes #4635     
In `crates/client-api/src/routes/database.rs` line 1111,
`lookup_database_identity` returns a `Result` but the error was handled
with `.unwrap()`, which panics instead of returning an HTTP 500.
Replaced it with `.map_err(log_and_500)?` to match the rest of the file.

---------

Co-authored-by: Zeke Foppa <196249+bfops@users.noreply.github.com>
Co-authored-by: Zeke Foppa <bfops@users.noreply.github.com>

crates/client-api/src/routes/database.rs

@@ -1107,7 +1107,12 @@ pub async fn set_names<S: ControlStateDelegate + Authorization>(
         })?;
 
     for name in &validated_names {
-        if ctx.lookup_database_identity(name.as_str()).await.unwrap().is_some() {
+        if ctx
+            .lookup_database_identity(name.as_str())
+            .await
+            .map_err(log_and_500)?
+            .is_some()
+        {
             return Ok((
                 StatusCode::BAD_REQUEST,
                 axum::Json(name::SetDomainsResult::OtherError(format!(