[Elastic Agent] Fix agent dashboard links for non default spaces

[P1llus]

What does this PR do?

Referencing dashboards with markdown needs to be space-aware. Currently it was using a hyperlink that would always choose the default space on many occasions, the PR simply changes the markdown links to the correct format.

Tested all the links on all the dashboards after the changes, and they are working fine.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

How to test this PR locally

Elastic Agent integration is installed by default, open up the Dashboards UI and click on the Agent Overview dashboard, then click on any of the links in the table of contents on the left, this should now work in any space for all the links.

Related issues

• Closes Links in the dashboards from elastic agent integration are not working in a multi space environment #6691

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Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[elasticmachine]

Pinging @elastic/elastic-agent (Team:Elastic-Agent)

[elasticmachine]

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Build stats

• Start Time: 2023-08-21T10:01:13.635+0000

• Duration: 14 min 16 sec

Test stats 🧪

Test	Results
Failed	0
Passed	37
Skipped	0
Total	37

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (0/0)	💚
Files	100.0% (0/0)	💚 16.667
Classes	100.0% (0/0)	💚 16.667
Methods	33.333% (25/75)	👎 -55.952
Lines	100.0% (0/0)	💚 13.333
Conditionals	100.0% (0/0)	💚

[elasticmachine]

Package elastic_agent - 1.11.1 containing this change is available at https://epr.elastic.co/search?package=elastic_agent