debugger: Enable setting debug panel dock position to the side (#29914)

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<img width="301" alt="Screenshot 2025-05-05 at 11 08 43 PM"
src="https://github.com/user-attachments/assets/aa445117-1c1c-4d90-a3bb-049f8417eca4"
/>


Setups the ground work to write debug panel persistence tests and allows
users to change the dock position of the debug panel.


Release Notes:

- N/A

crates/debugger_ui/src/tests.rs

@@ -23,6 +23,8 @@ mod debugger_panel;
 #[cfg(test)]
 mod module_list;
 #[cfg(test)]
+mod persistence;
+#[cfg(test)]
 mod stack_frame_list;
 #[cfg(test)]
 mod variable_list;