sidepanel was hidden by mistake on channels, fixed some errors in BrowseResourceMetadata

[nucleogenesis]

Summary

Takes care of a couple issues around showing metadata side panel with BrowseResourceMetadata.

1. In TopicsPage the side panel was being coerced with some /deep/ css to be off screen so I removed that.
2. Some errors around keys not being available on undefined w/ the ancestors splicing business in showing channel locations were showing up and I made sure it always got an object instead of undefined.

References

Fixes do not reference an issue (that I know of anyway).

Reviewer guidance

Go to a channel (with the black top bar) and try to open the side panel. Do you see everything where it ought to be?

Check the console, any errors about title or similar not being defined? Any errors at all pointing to BrowseResourceMetadata directly?

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Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• [x ] PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[marcellamaki]

Looks good! And thanks for fixing a bug that I suspect I caused 😊