Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/7a5da83d3763
Author: Yura Zenevich <yura.zenevich@gmail.com>
Desc: Merge pull request #24863 from jobara/1069380

Bug 1069380 - Use link role instead of button for open action in cards view

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https://hg.mozilla.org/integration/gaia-central/rev/a39c47800a74
Author: Justin Obara <obara.justin@gmail.com>
Desc:  Bug 1069380 - Use link role instead of button for open action in cards view

Changes the button role on the screenshotView to link, and adds the aria-hidden=true attribute to the iconButton to hide it from AT's. Added tests to ensure the aria properties in the cards view.
Bumping manifests a=b2g-bump