docs(splitbutton): fix spectrum link

[csantos1113]

Description

Update spectrum link because the one introduced in #2134 seems to be failing and it isn't the official public documentation anyway

How and where has this been tested?

Please tag yourself on the tests you've marked complete to confirm the tests have been run by someone other than the author.

Open the Docs Site for the Split Button component:

• Ensure you can see updated Usage Notes

Regression testing

Validate:

1. A legacy documentation page (such as accordion), including:

• The page renders correctly
• The page is accessible
• The page is responsive

2. A migrated documentation page (such as action group), including:

• The page renders correctly
• The page is accessible
• The page is responsive

Screenshots

To-do list

• I have read the contribution guidelines.
• I have updated relevant storybook stories and templates.
• I have tested these changes in Windows High Contrast mode.
• If my change impacts other components, I have tested to make sure they don't break.
• If my change impacts documentation, I have updated the documentation accordingly.
• ✨ This pull request is ready to merge. ✨

[pfulton]

Thanks for catching this, @csantos1113! The original URL does work, but only for Adobe employees, as it's behind a firewall. So, we probably never noticed that it wasn't accessible for non-Adobe folks.

[csantos1113]

Thanks for catching this, @csantos1113! The original URL does work, but only for Adobe employees, as it's behind a firewall. So, we probably never noticed that it wasn't accessible for non-Adobe folks.

Thanks for the approval. I wonder if there are more links that need to be updated