Ensure fetch is not called when navigating backwards

[jordojordo]

Summary

Fixes #11931

The issue was caused due to a watch on the $route.query object, when that changed we would call $fetch a second time before leaving the page.

Occurred changes and/or fixed issues

Added a condition to check for an empty query object before calling $fetch

Technical notes summary

When navigating backwards (from apps/charts/chart to apps/charts) the query object is empty, the watch is still used when the route contains the query, e.g. when selecting a different version from the Readme view.

Areas or cases that should be tested

• Navigate to apps/charts
• Select a chart
• Ensure the version select still works
• Navigate back to the charts page
• Ensure no errors are logged in the console

Areas which could experience regressions

Screenshot/Video

2024-09-20.13-52-58.mp4

Checklist

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