[feature] Improve feedback message for matches() assertion when used with undefined

[ngarbezza]

Is your feature request related to a problem? Please describe.

When we end up having an unexpected object in the actual part of the matches assertion, the feedback message is not ideal:

[ERROR] prints initial configuration on start
  => TypeError: Cannot read properties of undefined (reading 'match')

Describe the solution you'd like

A message saying: "Actual object needs to be a regular expression, got undefined".

Describe alternatives you've considered

None

Additional context

N/A