Create SSOT for Company Logos used on billing and trial pages

Problem

We now have 2 sources of truth for the marketing/promotional logos in the app.

Automated follow-up context

The following discussion from !194320 (merged) should be addressed:

• @dstull started a discussion: (+2 comments)

  @syarynovskyi during paring we were looking at Add back logos for trial registrations page (!195055 - merged) and such.

  We were wondering if it were possible to use a SSOT for these svgs again. Do you think it is possible to use image_tag here again as a way to achieve that SSOT between Add back logos for trial registrations page (!195055 - merged) and this use? Or something else?

  /cc @rliu-gl

Added context

In Update Company Logos on billing page in Dark Mode (!194320 - merged) due to a UI need for styling that image_tag couldn't handle per !194320 (comment 2595242516):

The main issue here is to change these logos' color between Dark and Light modes. I couldn't achieve that with the image_tag. Maybe we can add some kind of border if that works for UX We can create an issue and investigate possible solutions, and then ask Jesse if that works. If needed, I can take care of that.

We moved the file based promotional SVG's into a partial ee/app/views/groups/billings/_trusted_by_logos.html.haml.

However, it was then noticed that we actually used those promotional SVG's in registration. See Add back logos for trial registrations page (!195055 - merged)

Requirements

From !194320 (comment 2595936526):

1. Have 1 source of truth for the svg.
2. Not change the UI display we currently have.
3. clearly see the name of the image and retain 'alt'.

Possible solutions

• re-explore image_tag and see if it works in some way. Or some other construct that allows us to retain a file based asset approach. Perhaps there is minor asset caching perf help there if it is file based 🤔
• use named helper methods and reference in both areas... not great