OKR: Admin Area-Network/ Package Registry Rate Limits

What does this MR do and why?

Updates the package registry rate limits, applying similar changes as in !70127 (merged) (which uses extremely similar limits and styling):

• Adds docs link, using the same style as the other sections in the network settings page.
• Moves the repeated Helps reduce request volume... line to a single line at the top of the section, as it applies to all the rate limits universally. Placed "below the fold", so it's only visible after expanding the section.
• Removes the H5 headers for every sub-section, which were just basically repeating each setting name. It's much simpler and easier to scan now.
• Copy edits the docs to match:
  • Updates the docs to match the UI text.
  • Creates a a proper CTRT task for updating each setting, and adds the defaults too.

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Quality

• Quality checklist confirmed

1. I have self-reviewed this MR per code review guidelines.
2. For the code that that this change impacts, I believe that the automated tests (Testing Guide) validate functionality that is highly important to users (including consideration of all test levels). If the existing automated tests do not cover this functionality, I have added the necessary additional tests or I have added an issue to describe the automation testing gap and linked it to this MR.
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6. I have confirmed that this change is backwards compatible across updates, or I have decided that this does not apply.
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3. I have considered the availability and reliability risks of this change. I have also considered the scalability risk based on future predicted growth
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• Security checklist confirmed

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• Deployment checklist confirmed

1. I have considered using a feature flag for this change because the change may be high risk. If I decided to use a feature flag, I plan to test the change in staging before I test it in production, and I have considered rolling it out to a subset of production customers before doing rolling it out to all customers. When to use a feature flag
2. I have informed the Infrastructure department of a default setting or new setting change per definition of done, or decided that this is not needed.

Related to #330221 (closed)