refactor(android/engine): Refactor updateSelection

[darcywong00]

Relates to #11360 and follows #11384 -

Applies suggested refactoring of updateSelection

• Eliminate selStart, selEnd, and result vars
• short-circuit checks (to return false)

User Testing

Setup Install PR build of Keyman for Android and enable Keyman as the default system keyboard

• TEST_INVERTED_SELECTION_RANGE : Using Keyman for Android as a system keyboard, ensure that backwards selection ranges do not crash the keyboard.

1. Select text (right to left), then drag one of the end points through and past the other one.
2. If the keyboard immediately disappears, or you see an error notification, FAIL this test.

• TEST_NORMAL_SELECTION_RANGE: Using Keyman for Android as a system keyboard, ensure that normal (forward) selection ranges do not crash the keyboard

1. Select text (left to right).
2. If the keyboard immediately disappears, or you see an error notification, FAIL this test.

[keymanapp-test-bot]

User Test Results

Test specification and instructions

• ✅ TEST_INVERTED_SELECTION_RANGE (PASSED): I tested this issue with the attached "Keyman 17.0.320-beta-test-11389" build on an Android 14 environment: Here is my observation. (notes)
• ✅ TEST_NORMAL_SELECTION_RANGE (PASSED): I followed steps 1 to 3 that were mentioned above. The keyboard did not disappear when selecting some text from left to right. When moving the text selection from left to right and right to left, it happens appropriately.

Test Artifacts

• Android
  • Keyman for Android apk
  • FirstVoices for Android 16.0 apk
  • FirstVoices Keyboards for Android apk
  • KeyboardHarness apk
  • Keyman for Android 16.0 apk
  • KMSample1 apk
  • KMSample2 apk

[dinakaranr]

• TEST_INVERTED_SELECTION_RANGE (PASSED): I tested this issue with the attached "Keyman 17.0.320-beta-test-11389" build on an Android 14 environment: Here is my observation.

1. Installed the "keyman-17.0.320.apk" file and gave all permissions to the application.
2. Checked the "Enable Keyman as system-wide keyboard" and set the keyboard as the default keyboard box on the settings page.
3. Open the Chrome browser, and then enter some text in the address bar and Google search box.
   The keyboard did not disappear when selecting some text from right to left. The keyboard stays on the screen when dragging the text selection from right to left.

• TEST_NORMAL_SELECTION_RANGE (PASSED): I followed steps 1 to 3 that were mentioned above. The keyboard did not disappear when selecting some text from left to right. When moving the text selection from left to right and right to left, it happens appropriately.

[keyman-server]

Changes in this pull request will be available for download in Keyman version 17.0.321-beta