Test Support Bundle Extended Collection

https://github.com/longhorn/longhorn/issues/6754

Test /proc/mounts file

Given Longhorn installed
When generated support-bundle
And proc_mounts file should exist in support-bundle/nodes//hostinfo/

Test multipath.config file

Given Longhorn installed
And /etc/multipath.config exists on cluster nodes
When generated support-bundle
And multipath.config should exist in support-bundle/nodes//hostinfo/

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