Apply 2195 also to client activity line chart

[yubiuser]

{Please ensure that your pull request is for the 'devel' branch!}

• I have read and understood the contributors guide, as well as this entire template.
• I have made only one major change in my proposed changes.
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What does this PR aim to accomplish?:

Apply 2195 also to client activity line chart

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/pi-hole-ftl-v5-16-web-v5-13-and-core-v5-11-1-released/56384/1