[APP-690] better handling of post languages language filtering (#893)

* add SelectLangBtn

* memoized objects that are created to reduce re-creation on re-render

* add langs when uploading post

* only send the top 3 languages otherwise backend will throw error

* mv ContentLanguagesSettings to folder

* add post languages settings modal and state

* fix typos

* modify feed manip to also check langs label on post

* Fix tests

* Remove log

* Update feed-manip.ts

* Fix syntax errors

* UI tuneups

* Show the currently selected languages in the composer

* fix linting

* Use a bcp-47 matching function

* Fix a duplicate language issue

* Fix web

* Dont include lang in prompt

* Make select language btn an observer

* Keep device languages on top of language selection UIs

* Fix android build settings

* Enforce a max of 3 languages in posts

* Fix tests

* Fix types

---------

Co-authored-by: Paul Frazee <pfrazee@gmail.com>

src/view/com/composer/select-language/SelectLangBtn.tsx

@@ -0,0 +1,56 @@
+import React, {useCallback} from 'react'
+import {TouchableOpacity, StyleSheet, Keyboard} from 'react-native'
+import {observer} from 'mobx-react-lite'
+import {
+  FontAwesomeIcon,
+  FontAwesomeIconStyle,
+} from '@fortawesome/react-native-fontawesome'
+import {Text} from 'view/com/util/text/Text'
+import {usePalette} from 'lib/hooks/usePalette'
+import {useStores} from 'state/index'
+import {isNative} from 'platform/detection'
+
+const HITSLOP = {left: 10, top: 10, right: 10, bottom: 10}
+
+export const SelectLangBtn = observer(function SelectLangBtn() {
+  const pal = usePalette('default')
+  const store = useStores()
+
+  const onPress = useCallback(async () => {
+    if (isNative) {
+      if (Keyboard.isVisible()) {
+        Keyboard.dismiss()
+      }
+    }
+    store.shell.openModal({name: 'post-languages-settings'})
+  }, [store])
+
+  return (
+    <TouchableOpacity
+      testID="selectLangBtn"
+      onPress={onPress}
+      style={styles.button}
+      hitSlop={HITSLOP}
+      accessibilityRole="button"
+      accessibilityLabel="Language selection"
+      accessibilityHint="Opens screen or modal to select language of post">
+      {store.preferences.postLanguages.length > 0 ? (
+        <Text type="lg-bold" style={pal.link}>
+          {store.preferences.postLanguages.join(', ')}
+        </Text>
+      ) : (
+        <FontAwesomeIcon
+          icon="language"
+          style={pal.link as FontAwesomeIconStyle}
+          size={26}
+        />
+      )}
+    </TouchableOpacity>
+  )
+})
+
+const styles = StyleSheet.create({
+  button: {
+    paddingHorizontal: 15,
+  },
+})