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

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https://hg.mozilla.org/integration/gaia-central/rev/6ebc50f9403e
Author: gitmai <mri@tid.es>
Desc: Merge pull request #24365 from gitmai/bug-1071710-contacts-change-new-string-id-for-sim-number

Bug 1070914 - [Contacts] [Settings] SIM Import label has disappeared

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https://hg.mozilla.org/integration/gaia-central/rev/2c93f0dee56d
Author: mai <mri@tid.es>
Desc: Bug 1070914 - [Contacts] [Settings] SIM Import label has disappeared
Bumping manifests a=b2g-bump