Be more selective for the sharing fallback

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extra : rebase_source : 8188f27b0eaab3d984f4f7acee222149e4665be1
Fixed fallout from localization changes: wrong labels in settings page and next button logic in issue reporter

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extra : rebase_source : 71a60a33ab6580c29f961f0704cc3c5a18a70a45
Fixed: Issue reporter broken in Firefox nightlies

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extra : rebase_source : b82a0ac69a96ac1acfe021a8b941b4362bd0d169
Change attribute name from _script to data-script to be standard-compliant