Translation results field is not cleared after completely clearing the input field

[acornestean]

[Affected versions]: Firefox Nightly (94.0a1/20210920212918)

[Affected Platforms]: Windows 10 x64

[Prerequisites]: Access https://mozilla.github.io/translate/.

[Steps to reproduce]:

1. Translate any text using any available language combination. For example, use: “Giovanni Antonio Grassi (10 September 1775 – 12 December 1849) was an Italian Jesuit who led many academic and religious institutions in the United States and Europe. Born in Lombardy, he studied at the Jesuit College in Polotsk, where he began his academic career. He was soon ordered to China as a missionary, but after traveling across Europe for two years attempting to secure passage, his orders were rescinded and he instead began teaching at Stonyhurst College in England.”
2. Once the translation has finished, delete/clear the entire contents of the input field
3. Notice the translation results field was not updated/cleared to reflect the lack of text from the input field.

[Expected]: The results field should update in real time in accordance with the input field.

NOTE: When partially deleting/clearing content from the input field, the results field gets properly updated.

[Actual]: The results field does not get updated/cleared when the entire input field is cleared.