[components] Better error message for failing entry points

[smackesey]

Summary & Motivation

Currently if there is an error when loading a dagster-components entry point, the whole process terminates unceremoniously with an ugly error.

This PR changes this behavior:

Entry points are loaded in a try-catch block. Any error loading an entry point causes a warning to be written to stdout about the failing entry point, and the entry point to be passed over so that the whole system doesn't blow up. The warning shows up in the dg output.

How I Tested These Changes

New unit test and manually (running dg component-type list in an env with a bad entry point).

[smackesey]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• [components] Better error message for failing entry points #27530 👈 (View in Graphite)
• [components] Improve error message for dg component scaffold <uninstalled-component> (BUILD-666) #27522
• [components] Add dg dev command (BUILD-578) #27481 : 1 other dependent PR (#27537 )
• [components] project_name -> code_location_name in scaffolded pyproject.toml #27480
• master

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