[Bug] "Paste/Select All" menu appears flipped and is backwards

[MadridSpain]

Steps to reproduce

1. Set Firefox 80 to its default settings
2. Log in to reddit.com
3. Go to someone's comment and hit "reply"
4. Type the following into the blank comment box (excluding quotation marks. Include the space):
   "> "
5. Longpress in the comment box.
6. Press the little menu bubble that pops up.

Expected behavior

Normally, you are given an option to either "Paste" or "Select All", in that order. Here are two screenshots of what normally happens:
Chrome-based Browser Screenshot:
https://imgur.com/a/si6Dd4H
Firefox Focus Screenshot:
https://imgur.com/a/q1nGyy9

Actual behavior

The menu is reversed. It is flipped backwards, so now if you tap where you normally tap on, you hit not "paste", but "select all". The menu is flipped. No other mobile browsers do this. Firefox 68 did not do this. It's extremely counter-intuitive and causes many people to accidentally hit the "select all" button instead of the "paste" button, because it's in the wrong place. All other times in Firefox 80, "paste" comes up first. But when the "Paste/Select All" menu comes up, Firefox 80 has it backwards. Screenshot below:
Firefox 80 Screenshot:
https://imgur.com/a/McYvj6N

Device information

• Android device: Samsung S8 (SM-G950FD Smartphone, latest version of Android operating system as of 2020/Sep/09)
• Fenix version: Firefox 80.1.2 (Build number 2015761283)

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