Error in deleting characters in a text field

To delete characters after defocusing the text field, you need to press the delete button as many times as the: number of characters * 2

### Versions

- Python: 3.9.9
- OS: Android
- Kivy: master
- Cython: latest
- OpenJDK: 17
- p4a: develop

```py
from kivy.app import App
from kivy.lang import Builder

kv = """
Screen:
TextInput:
size_hint_y: None
height: dp(45)
hint_text: "1"
write_tab: False
pos_hint: {"top": 0.9}

TextInput:
size_hint_y: None
height: dp(45)
hint_text: "2"
write_tab: False
pos_hint: {"top": 0.7}
"""

class Test(App):
def build(self):
return Builder.load_string(kv)

Test().run()
```

**buildozer.spec**
```
[app]

title = My Application

package.name = myapp

package.domain = org.test

source.dir = .

source.include_exts = py,png,jpg,kv,atlas

version = 0.1

requirements = kivy==master

orientation = all

osx.python_version = 3

osx.kivy_version = 2.1.0

fullscreen = 0

android.api = 33

android.minapi = 21

android.ndk = 25b

android.accept_sdk_license = True

android.enable_androidx = True

android.logcat_filters = *:S python:D

android.archs = arm64-v8a, armeabi-v7a

android.allow_backup = True

p4a.branch = develop

p4a.bootstrap = sdl2

[buildozer]

log_level = 2

warn_on_root = 1
```

https://user-images.githubusercontent.com/40869738/211171901-9a0d5a2d-2b11-4c29-99aa-7d420ba73907.mp4

Start by reproducing the provided two-TextInput example on Android with the listed Python, Kivy, and p4a versions, then compare deletion before and after defocusing. The issue names no source file or test, so trace the Android text-input handling and add a regression test for the reported deletion behavior; done means characters delete once per press.

Written by the indexing model from the issue text.