Limit MAXLOGAGE to 24h, just like FTL

[rdwebdesign]

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What does this PR aim to accomplish?:

Fix #1825.

If MAXLOGAGE is set inside pihole-FTL.conf to anything greater than 24, it is already limited by FTL (and the graphic is limited to 24 hours), but the graphic title shown on the dashboard is using the wrong (not limited) value.

How does this PR accomplish the above?:

Limiting the interval for the dashboard graphic title to a maximum of 24 hours, since FTL already limits this value.

What documentation changes (if any) are needed to support this PR?:

I think this was already changed in the docs.

[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-v5-14-web-v5-11-and-core-v5-9-released/53529/1