Revise toolshed config dependency check error message in repository install manager

[guerler]

Follow-up to #8660. Fixes #8715.

[jmchilton]

It feels like the check should be modernized and fixed but eliminated entirely. I'm fine with this though - we don't have any testing to verify the check works clearly so if we decide to do this better later we can add that with tests.

[jdavcs]

app.tool_dependency_dir can be None. I'm afraid I can't estimate whether this check is needed here (I don't know this part of the codebase well enough), so I'll rely on @jmchilton 's opinion.

[nsoranzo]

I cannot reproduce #8715, is this still needed after #8696 was merged? If yes, how to reproduce?

[nsoranzo]

app.config.tool_dependency_dir can be None, while I don't think app.tool_dependency_dir should be None just because tool_dependency_dir is not set in galaxy.yml .

See https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/config/__init__.py#L1102 and https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/tool_util/deps/__init__.py#L83

[guerler]

This underlying issue seems to be fixed now by a recent change in dev. Thank you @nsoranzo! Should we still remove the check here or at least revise the message?

[nsoranzo]

Should we still remove the check here or at least revise the message?

I think we can revise the message to something like "Tool dependencies installation is disabled in your configuration files."