Fix issue where incognito mode was not enabled in text story creation.

app/src/main/java/org/thoughtcrime/securesms/util/EditTextExtensions.kt

@@ -0,0 +1,22 @@
+package org.thoughtcrime.securesms.util
+
+import android.widget.EditText
+
+/**
+ * Since this value is only supported on API26+ we hard-code it here
+ *  to avoid issues with older versions. This mirrors the approach
+ *  taken by [org.thoughtcrime.securesms.components.ComposeText].
+ */
+private const val INCOGNITO_KEYBOARD = 16777216
+
+/**
+ * Enables or disables incognito-mode for the keyboard. Note that this might not
+ * be respected by all IMEs.
+ */
+fun EditText.setIncognitoKeyboardEnabled(isIncognitoKeyboardEnabled: Boolean) {
+  imeOptions = if (isIncognitoKeyboardEnabled) {
+    imeOptions or INCOGNITO_KEYBOARD
+  } else {
+    imeOptions and INCOGNITO_KEYBOARD.inv()
+  }
+}