BuddyPress Connector: Check for BP dependencies before blindly assuming they're available

[dd32]

Fixes #1516.

Untested, this is just a visual patch from looking at the code.

Checklist

• Project documentation has been updated to reflect the changes in this pull request, if applicable.
• I have tested the changes in the local development environment (see contributing.md).
• I have added phpunit tests.

Release Changelog

• Fix: Avoid potential fatal errors when using BuddyPress and Stream.

Release Checklist

• This pull request is to the master branch.
• Release version follows semantic versioning. Does it include breaking changes?
• Update changelog in readme.txt.
• Bump version in stream.php.
• Bump Stable tag in readme.txt.
• Bump version in classes/class-plugin.php.
• Draft a release on GitHub.

[dd32]

This PR probably avoids the fatals, but the links in network admin might be incorrect too... It might be that the links should be using get_admin_url( $blog_id, ... ) instead such as they go the correct location...

[tharsheblows]

@delawski @dd32 This fixes the fatal errors for me --

This PR probably avoids the fatals, but the links in network admin might be incorrect too... It might be that the links should be using get_admin_url( $blog_id, ... ) instead such as they go the correct location...

I think we should merge this now and I'll open another issue to update those links.

[tharsheblows]

Added issue for action links: #1520

[dd32]

Thank you @tharsheblows!