Add missing translations for context menu

[Gabriel Dufresne (GabrielDuf)]

Summary

• Fix untranslated text in the package-list right-click context menu on the Avalonia build. The four context menu builders (DiscoverSoftwarePage, InstalledPackagesPage, SoftwareUpdatesPage, PackageBundlesPage) were calling CoreTools.AutoTranslated(...) directly on plain MenuItem.Header. AutoTranslated is a no-op marker used in WinUI alongside a BetterMenuItem wrapper whose Text setter re-runs CoreTools.Translate(). Avalonia uses plain MenuItem, so the marker strings never got translated. Switched all call sites to CoreTools.Translate(...).
• Add the two new English keys introduced in support of minimum age directly in managers  #4809 ("Partial" and "{pm} only provides release dates for some of its packages, so this setting will only apply to those packages") to all 58 non-English language files, bringing each locale back to 100% completion.
• Fix the Russian translation of the "Reload" toolbar button (issue Incorrect translation #4812).