Fix: Fix agency link regression

[machikoyasuda]

closes #2590

How did this bug happen

A regression was introduced in #2526. When I removed the CA State Web Template, it removed this piece of CSS:

Since the agency name area uses a <label> element, the element was getting font-weight: 700 from there. Now that the state web template is no longer being used, the element lost its bold font.

What this PR does

• Changed the label to a regular p. (Using <label> for something that is not a form is not semantic.)
• Created a .h4 CSS class, with the same exact attributes of the h4 element. And used the h4 class on this agency name, to get the h4 styles.
• Added mt-1 to get the lines to be 4px away from each other.

QA

• Note: Bug: Help page transit agency link focus rings aren't rounded on Firefox #2547 still exists. I still don't really know exactly why this is happening, and so I haven't figured out how to fix it.

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.

[thekaveman]

LGTM