Fix cursor not showing when tabbing into multiline TextInput

[christophpurrer]

Please select one of the following

• I am removing an existing difference between facebook/react-native and microsoft/react-native-macos 👍
• I am cherry-picking a change from Facebook's react-native into microsoft/react-native-macos 👍
• I am making a fix / change for the macOS implementation of react-native
• I am making a change required for Microsoft usage of react-native

Summary

This bug happens because RCTUITextView (which multiline TextInput uses) was overriding NSTextView's becomeFirstResponder method and didn't call [super becomeFirstResponder].
This seems to mess with AppKit's logic of drawing the cursor initially.

This is alluded to in the docs for [NSTextView becomeFirstResponder]:

If the previous first responder was not a text view on the same layout manager as the receiving text view, this method draws the selection and updates the insertion point if necessary.

Simply switching to call [super becomeFirstResponder] led to a cryptic exception within AppKit. This was likely because in the reactFocus (and reactFocusIfNeeded) we were calling becomeFirstResponder directly.
The docs for [NSResponder becomeFirstResponder] say:

Use the NSWindow makeFirstResponder: method, not this method, to make an object the first responder. Never invoke this method directly.

There necessary fixes are already part of 84c0863#diff-8a3ec110f2ee884d2ef078efddc4ebba9413c7e8cb90b6f5cebff19b2c0a1951 and hence not included in this diff

#if TARGET_OS_OSX // [TODO(macOS GH#774). 
	if (![[self window] makeFirstResponder:self]) {
#else
// ...
}

- (void)reactFocusIfNeeded
{
	if (self.reactIsFocusNeeded) {
#if TARGET_OS_OSX // [TODO(macOS GH#774)
		if ([[self window] makeFirstResponder:self]) {
#else
// ...
}

Changelog

[macOS] [Fixed] - Fix cursor not showing when tabbing into multiline TextInput

Test Plan

Using this example

            <>
              <View
                focusable={true}
                style={styles.row}
                validKeysDown={['g', 'Escape', 'Enter', 'ArrowLeft']}
                onKeyDown={this.onKeyDownEvent}
                validKeysUp={['c', 'd']}
                onKeyUp={this.onKeyUpEvent}></View>
              <TextInput
                blurOnSubmit={false}
                placeholder={'Singleline textInput'}
                multiline={false}
                focusable={true}
                style={styles.row}
                validKeysDown={['ArrowRight', 'ArrowDown']}
                onKeyDown={this.onKeyDownEvent}
                validKeysUp={['Escape', 'Enter']}
                onKeyUp={this.onKeyUpEvent}
              />
              <TextInput
                placeholder={'Multiline textInput'}
                multiline={true}
                focusable={true}
                style={styles.row}
                validKeysDown={['ArrowLeft', 'ArrowUp']}
                onKeyDown={this.onKeyDownEvent}
                validKeysUp={['Escape', 'Enter']}
                onKeyUp={this.onKeyUpEvent}
              />
            </>

Before

before.mov

After

after.mov

[Saadnajmi]

Thanks! Glad my changes are kind of "followed up" here