Update Firefox install to install from Mozilla since snap is not avaialable

[eng3]

The Dockerfile uses matlab-deps which is based on an ubuntu image. The current firefox install line in the Docerfile installs the package from the Ubuntu repository which relies on snap. Snap is not installed in the container and thus firefox will not run along with any of the help pages.

Recommend modifying Dockerfile to install firefox properly.

Example: Add before firefox install: (based on firefox install instructions) RUN install -d -m 0755 /etc/apt/keyrings && wget -q https://packages.mozilla.org/apt/repo-signing-key.gpg -O- | sudo tee /etc/apt/keyrings/packages.mozilla.org.asc > /dev/null && echo "deb [signed-by=/etc /apt/keyrings/packages.mozilla.org.asc] http://packages.mozilla.org/apt mozilla main" | sudo tee -a /etc/apt/sources.list.d/mozilla.list > /dev/null && echo "Package: *\nPin: origin packages.mozilla.org\n Pin-Priority: 1000" | tee /etc/apt/preferences.d/mozilla

(and add wget to deps list)