fix: Add tolerance buffer for gauge real-time updates with clock drift

[harshaljanjani]

First contribution!

Closes #8019

Describe your changes:

→ Fixes gauge component not updating consistently in real-time mode when time bounds end is set to "now". The gauge was rejecting telemetry data with timestamps slightly in the future due to clock drift / network latency / server time differences. This fix adds a 1-second tolerance buffer to the end-of-bounds check, allowing near-future data to be accepted while still filtering out genuinely out-of-bounds telemetry.

Steps to Reproduce the Bug (Before Fix)
→ Open the tutorial in browser (https://github.com/nasa/openmct-tutorial)
→ Click "Create" → "Gauge"
→ Save the gauge in "My Items"
→ Click "Create" → "Overlay Plot"
→ Save the plot in "My Items"
→ Expand "Example Spacecraft" in the left tree
→ Drag "Generator Temperature" onto the Gauge object in the tree
→ Drag "Generator Temperature" onto the Plot object in the tree
→ Navigate to the Gauge view

Observed (Buggy) Behavior:
❌ Gauge updates sporadically (every 20-25 seconds)
❌ Plot updates smoothly and continuously
❌ Gauge and plot have inconsistent update frequencies despite receiving the same telemetry stream

Steps to Verify the Fix (After Fix)
→ Follow the same reproduction steps above
→ Navigate between Gauge and Plot views

Expected (Fixed) Behavior:
✅ Gauge updates smoothly and continuously (multiple times per second)
✅ Plot updates smoothly and continuously
✅ Both gauge and plot have consistent update frequencies
✅ Gauge shows current real-time values without delay

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• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
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Author Checklist

• Changes address original issue?
• Tests included and/or updated with changes?
• Has this been smoke tested?
• Have you associated this PR with a type: label? Note: this is not necessarily the same as the original issue.
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• Testing instructions included in associated issue OR is this a dependency/testcase change?

Reviewer Checklist

• Changes appear to address issue?
• Reviewer has tested changes by following the provided instructions?
• Changes appear not to be breaking changes?
• Appropriate automated tests included?
• Code style and in-line documentation are appropriate?

[harshaljanjani]

cc: @shefalijoshi @jvigliotta @akhenry

[harshaljanjani]

Good day, any updates on this PR?
cc: @shefalijoshi @jvigliotta @akhenry