Add warning to inform user when multiple chips are used

[AlessandroPierro]

User story

As a user, I want to [capability] to [benefit].

Conditions of satisfaction

• An optional list of conditions that have to be fulfilled for this feature to be complete.
• For example: "Users can add both individual items and lists as parameters."

Acceptance tests

• An optional list of tests that should be written to automatically test the new feature.