Backport of docs: Clarify need to reload or restart Client Agent on Mac into release/0.17.x

[hc-github-team-secure-boundary]

Backport

This PR is auto-generated from #5183 to be assessed for backporting due to the inclusion of the label backport/website.

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The person who merged in the original PR is:
@Dan-Heath
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The below text is copied from the body of the original PR.

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From a Slack conversation, the difference between restarting the Client Agent vs. reloading the configuration file could be confusing to users. This PR attempts to clarify the difference as well as the benefit to reloading only, when possible.

View the update in the preview deployment

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Overview of commits

• d641e09

• c4fca0c

• 0604a5b

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[Dan-Heath]

Closed in favor of #5188