Reactive Forms/FormControl Have Incorrect Values When Using iOS QuickPath/Slide to Type

Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):

• CLI: 8.2.3
• Cross-platform modules: 8.1.1
• Android Runtime: 8.1.1
• iOS Runtime: 8.2.1
• Plugin(s): iqkeyboardmanager (2.0.0)
• NativeScript-Angular: 12.2.0
• Angular: 12.2.13

Describe the bug
When using swipe to type/QuickPath on an iOS keyboard in a reactive form, the word input with QuickPath temporarily replaces the value of the control with just that word instead of appending to the control's previous value. Another input into the keyboard subsequently returns the value back to the full expected value.

To Reproduce

1. Have a TextField bound to a FormControl with the formControl attribute.
2. Subscribe to the control's valueChanged event and output the value each time the value changes.
3. Start inputting a word into the text field, then add a space, for example, "Test ".
4. Now use QuickPath/slide to type to input another word, like "test" again.
5. The last output you see will be "test" instead of "Test test".
6. Input a space, the output will return to the full value of the control.

Expected behavior
When using slide to type/QuickPath, form controls should retain the full value of those controls and emit those values as usual to valueChanged.

按照列出的 QuickPath 步骤，使用绑定到 Angular FormControl 的 iOS TextField 重现该问题，并订阅其 valueChanged 事件。跟踪 TextField 的值传播到表单控件的位置，并验证在滑动输入期间以及随后输入空格后，会发出完整的值，例如“Test test,”。