Importing a dependent component overwrites its changed dependencies

[davidfirst]

Describe the bug

When importing a component, Bit normally checks whether there are changes to the component and throw an error if they are.
However, when a dependency is imported to the workspace and a user is now importing its dependent it overrides the dependency although it has changed.

Steps to Reproduce

1. create two components compA => compB, whereas compA requires compB.
2. import compB and change it.
3. import compA.
   Notice how compB has been overridden.

Expected Behavior

In case the dependency has changed, it should throw an error saying it can't import the component due to the change.

Also, change the error message to include a suggestion of using --merge flag, as follows:
unable to import the following components due to local changes, use --merge flag to merge your local changes or use --override flag to override them.

Specifications

• Bit version: 14.2.3
• Node version: Any
• npm / yarn version: Any
• Platform: Any
• Bit compiler (include version): N/A
• Bit tester (include version): N/A

CC: @itaymendel