#656

This fixes a bug with cy.contains.

- A suitable version was not available after update of Angular
- Reactivate test for valid pages

with ng update @angular/material@16 @angular/cdk@16
- run npm audit fix

- run npm audit fix to fix some critical vulnerables

Uses external software 'MathLive'.

Distpacker issues with mathlive have been solved in a custom 
distpacker.ts in scripts-folder. This is now used instead of the 
distpacker from the npm package.

#298

This reverts commit da09ac1e.