Upload modal box disappear if click is made outside the box, or in the title box

Description:

Using the Web portal, on any channel: If I click the + button to add a picture from my computer, then I choose a file, the modal box will immediately close if I do one of the following:

• click outside of the modal box
• highlight the filename field using a long left clic then release it outside the modal box, when I want to change this text.

Steps to reproduce:

1. Go to the web application
2. Open a channel if not already
3. Click on the bottom right + button then select Computer
4. Pick a picture from your computer
5. Highlight the filename field using your mouse, by clicking left at the begining of the string then moving over the name, continue until your cursor is out of the white modal box and release your mouse left button

Expected behavior:

The modal box must stay opened if I release my left button outside the upload modal box
It should also stay open if I click outside of it, that could happens by mistake and I will have to redo the upload again.
In fine, only the cancel button should close the modal box.

Actual behavior:

If we click outside the modal box, it closes it without a warning.
If we select a text using the left button of our mouse and release it outside the box, it closes the box without a notice as well.

Server Setup Information:

• Version of Rocket.Chat Server: 3.15.0
• Operating System: Docker (Centos 8)
• Deployment Method: docker
• Number of Running Instances: 1
• DB Replicaset Oplog: 1
• MongoDB Version: 4.0

Client Setup Information

• Desktop App or Browser Version: Google Chrome Version 91.0.4472.101
• Operating System: Windows 10 21H1

Additional context

Relevant logs:

Start by reproducing the upload flow in the web application: open a channel, choose Computer from the + menu, select an image, and test clicks and drag selections ending outside the modal. Trace the upload modal entry point and its outside-click handling; done means accidental outside clicks or mouse releases no longer close the modal, while Cancel still does.