Upon further investigation, I discovered that the microphone icon appears in the address bar ONLY if you select Google as your default search engine.

If you select any of the other available search engines for the Firefox browser on Android, the microphone disappears from the search bar. Because I was using Duck Duck Go, the latest update caused the microphone to vanish.

I find that very strange considering that Android is a Google product, so you would think that all the features would be available when the phone is being used.

However, it appears our giant tech overlord wants people to ONLY use Google for searching so that every word spoken and typed can be stored and tracked.

There is a workaround, and that is to use the microphone icon just above the numbers on the keyboard, but it is not nearly as effective as the microphone that used to appear in the far right of the search bar. The keyboard microphone uses the Samsung settings and it doesn't recognize spoken words as well.

Hopefully, one of the brilliant Firefox developers can figure out a way to bring the microphone back to the search bar on the Android app regardless of the default search engine.

Since privacy concerned individuals mostly use Firefox. The feature was disabled highly likely because of that.