Provide guidance about Microscope components comparison

[strambc]

Problem: When comparing two microscopes in MME, it's not obvious that the user needs to open the Component Explorer and pick a Component Category to see the comparison.

Ask: Add a UI cue (tooltip, hint, or highlight) that guides the user to the Component Explorer and prompts them to select a Component Category.

Possible solutions:

1. Change the text "No records to display" with "To compare a hardware component across the selected microscopes, click the '+' next to its category in the Component Explorer (left sidebar)."

2. Add a tooltip with the following two-line text: "Compare hardware across selected microscopes.
   Click the '+' next to a component category in the Component Explorer (left)."

3. Proposed solution: Display a warning in the comparison view when no selection has been made in the Component Explorer.
   Warning text:
   "To compare a hardware component across the selected microscopes, click the '+' next to its category in the Component Explorer (left sidebar)."