feat: add Angular Signals CT Harness for Angular 17.2 and up for users to be able to use Angular Signals within their component tests (#29621)

* direct copy paste of angular npm package to angular18 (no changes)

* feat: implement angular-signals test hardness to support angular signals

add changelog entry and build binary [run ci]

rename angular18 to angular-signals until we are able to merge back into core package [run ci]

fix linting job [run ci]

make sure angular-signals harness is copied to cli after build [run ci]

add project fixture directory to angular 18 and build binaries for newly named branch

run ci

update cache [run ci]

bust nx cache [run ci]

bust cache on linux [run ci]

try busting the cache... again [run ci]

usually helps when you have the correct build output... [run ci]

fix issue where component internal props were getting blown away when user would not set prop in componentProperties [run ci]

* update test harness description

* add built-in control flow tests with signals

* make sure to clean up rxjs observables in order to prevent a memory leak

* address comments from code review

* yarn lock

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Co-authored-by: Jennifer Shehane <jennifer@cypress.io>