debugger beta: Move path resolution to resolve scenario instead of just in new session modal (#31185)

This move was done so debug configs could use path resolution, and
saving a configuration from the new session modal wouldn't resolve paths
beforehand.

I also added an integration test to make sure path resolution happens
from an arbitrary config. The test was placed under the new session
modal directory because it has to do with starting a session, and that's
what the new session modal typically does, even if it's implicitly used
in the test.

In the future, I plan to add more tests to the new session modal too.

Release Notes:

- debugger beta: Allow configs from debug.json to resolve paths

crates/debugger_ui/src/tests.rs

@@ -25,6 +25,9 @@ mod inline_values;
 #[cfg(test)]
 mod module_list;
 #[cfg(test)]
+#[cfg(not(windows))]
+mod new_session_modal;
+#[cfg(test)]
 mod persistence;
 #[cfg(test)]
 mod stack_frame_list;