Bumping gaia.json for 1 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/f5db40c5dd79
Author: John Ford <john@johnford.info>
Desc: Revert "Merge pull request #12892 from comoyo/value_selector_inputcontext"

This reverts commit 47c3ccfc7682d7caeeb8a921153caf8cefc5b480.