fix: replay timestamps

[daibhin]

Problem

Closes https://github.com/PostHog/posthog/issues/21834 Addresses https://posthog.slack.com/archives/C03PB072FMJ/p1714032531933589

Changes

Switch button to use monospaced font to stop jumping

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On top of the issue called out by the customer the inspector timestamps did not match the player toggle

Before	After

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Also fixes a performance issue given the TZLabel assumes that the timestamp is always changing which means unnecessary intervals being computed every second. And recomputes the timezone every second, for every timestamp on the page:

Luckily for us the inspector is a virtualized list or the number of intervals would be much greater.

You can see the blips in CPU every second as these timers are processed (even when the recording is paused). Afterwards the CPU line looks flat.

Before	After

(Fix for the TZLabel component coming in a future PR)

[github-actions[bot]]

Size Change: +524 B (0%)

Total Size: 1.05 MB

ℹ️ View Unchanged

Filename	Size	Change
frontend/dist/toolbar.js	1.05 MB	+524 B (0%)

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