[Ingest Manager] Add links and fix problems found during UI text edits

[dedemorton]

We found these issues when we were editing the UI text (#74818), but I didn't want to fix them in that PR because they changed behavior (not just text):

• Make "Gold subscription" an active link in the text "Requires a Gold subscription." New issue [Ingest Manager] Add links to license management to Settings flyout #76502
• Make "Datasets" an active link in the text "Go to Datasets to view your data." [Ingest Manager] Wording & linking improvements #76284
• In the Add agent flyout, it would be helpful to add a description before the tabs so novice users will understand what an Elastic Agent is. Possibly something like: "Add Elastic Agents to your hosts to collect data and send it to the Elastic Stack." [Ingest Manager] Wording & linking improvements #76284
• The "Start the agent" section in the standalone instructions only covers the linux/macOS flavor of the run command. Is that intentional? Why not use the same commands that are shown on the tab with the Fleet steps? New issue [Ingest Manager] Improve agent standalone installation instructions #76500
• In the text "Before enrolling agents, set up Fleet. Go to Fleet." Make "set up in Fleet" a link so that "Go to Fleet is not required" [Ingest Manager] Wording & linking improvements #76284

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[skh]

Hi,

Make "Gold subscription" an active link in the text "Requires a Gold subscription."

I'm having a UX issue with this one. Right now, this is how the settings flyout looks like with a basic license:

The disabled option is not clickable, and the cursor clearly indicates that when hovering over the label text. I'm not sure if nudging a link into that place is a good solution (if it's possible at all with the EUI component that's used), but I'm also not sure where and how else to indicate that this setting needs a gold subscription.

@hbharding I could use your help here -- what do you think? Do we have some canonical way of marking specific settings as needing a higher subscription level?

[skh]

I've added new issues for the first and fourth item in the list. The others are implemented in #76284.

Once that is merged, I'll close this issue.