chore: add ionic angular example

[fadi-george]

Description

One Line Summary

• add angular ionic example for verification of different user setups

Details

• adds new IonicAngular example folder
• moves out the build shell script to use for both example projects
  • does the following to avoid using the bun cache:

rm -rf node_modules/onesignal-cordova-plugin
bun pm cache rm
bun i

Manual testing

• run ionic cap sync ios. it should error similar to what users reported here:
  [Question] Version 5.2.18 doesn’t work for me — am I doing something wrong? #1116 (comment)

➜  IonicAngular git:(fg/add-angular-example) ✗ ionic cap sync ios 
> npm run ionic:build -- --project=app

> IonicAngular@0.0.1 ionic:build
> ../scripts/build.sh IonicAngular --project=app

$ bun run build:vite
$ vite build
vite v7.1.12 building for production...
✓ 12 modules transformed.
Entry module "www/index.ts" is using named and default exports together. Consumers of your bundle will have to use `chunk.default` to access the default export, which may not be what you want. Use `output.exports: "named"` to disable this warning.

...

+ onesignal-cordova-plugin@../../onesignal-cordova-plugin.tgz

✔ Browser application bundle generation complete.

./src/app/app.component.ts:12:6-33 - Error: export 'default' (imported as 'OneSignal') was not found in 'onesignal-cordova-plugin' (module has no exports)

./src/app/app.component.ts:12:34-50 - Error: export 'LogLevel' (imported as 'LogLevel') was not found in 'onesignal-cordova-plugin' (module has no exports)

./src/app/app.component.ts:13:6-26 - Error: export 'default' (imported as 'OneSignal') was not found in 'onesignal-cordova-plugin' (module has no exports)

./src/app/app.component.ts:14:6-21 - Error: export 'default' (imported as 'OneSignal') was not found in 'onesignal-cordova-plugin' (module has no exports)


[ERROR] An error occurred while running subprocess npm.
        
        npm run ionic:build -- --project=app exited with exit code 1.
        
        Re-running this command with the --verbose flag may provide more
        information.
➜  IonicAngular git:(fg/add-angular-example) ✗ 

Will follow up in a separate pr with a fix.

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.

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This change is