LIMS-2387: Add units to molecular mass field

[ndg63276]

JIRA ticket: LIMS-2387

Summary:

The Molecular Mass field on the protein page has no units, we should add "Da", and display some text saying what this can be used for.

Changes:

• Add units and help text to molecular mass field on "View protein" page
• Fix CSS so that a span.label element inside a label element is not 28% of 28% wide
• Don't show ended commissioning visits on the home page

To test:

• Go to a protein page, eg /proteins/pid/707730
• Check there are now units and help text next to molecular mass
• Check the label all goes on a single line
• Go to the home page, check the i03 commissioning visit is not cm45865-2 as it has ended