Disable the second possible filters query on first render

[bprusinowski]

Currently, in some cases we fire the possible filters query twice:

• when initializing a chart from cube,
• when first mounting the left filters panel.

We should investigate if there's a need to fire the second query again, given that we assured the values were already "correct" by the first one. If we don't need to fetch it, we should disable firing the second query on the first render.

cc @Rdataflow