[roq-scripts] Prefer conda to mamba

[thraneh]

mamba uses libmamba which depends on fmt 9.x

The roq-* packages require fmt 10.x

This is how we get conflicts:

• When mamba is used to install, it tries to find packages compatible with the requirements.
• It then finds an ancient version of mamba (probably without a fmt dependency) and decides to downgrade itself.
• This in turn downgrades openssl to 1.1.1 which is EOL (should be 3.1.x)
• Everything depends on openssl ==> conflict!

We don't get these issues when using conda to install. So, unfortunately, we're forced to prefer conda right now.

Best practices should also use conda install --freeze-installed [...] to avoid unwanted downgrades.