chore: fix for missing redirects on @nativescript/angular

[DickSmith]

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• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• All existing tests are passing: https://github.com/NativeScript/nativescript-dev-webpack/blob/master/CONTRIBUTING.md#testing-locally-by-running-e2e-tests
• Tests for the changes are included.

What is the current behavior?

ERROR in __REDACTED__/node_modules/@nstudio/nativescript-checkbox/angular/index.js Module not found: Error: Can't resolve 'nativescript-angular/forms/value-accessors/base-value-accessor' in '__REDACTED__/node_modules/@nstudio/nativescript-checkbox/angular' 

ERROR in __REDACTED__/node_modules/nativescript-drop-down/angular/index.js Module not found: Error: Can't resolve 'nativescript-angular/forms/value-accessors/base-value-accessor' in '__REDACTED__/node_modules/nativescript-drop-down/angular' 

ERROR in __REDACTED__/node_modules/@nstudio/nativescript-checkbox/angular/index.js Module not found: Error: Can't resolve 'nativescript-angular/lang-facade' in '__REDACTED__node_modules/@nstudio/nativescript-checkbox/angular' 

What is the new behavior?

From what I've seen for the @nativescript/angular package, all mappings should be 1-1 anyway, so this should work, any exceptions to that assumption can also be remapped here for the specific cases.
Fixes/Implements/Closes:
nstudio/nativescript-checkbox#118
PeterStaev/NativeScript-Drop-Down#229

[rosen-vladimirov]

Closing as the suggested changes were already merged in this PR
Thanks for the great idea @DickSmith