* Add a new `allowSearchSuggestions` property to the query context. It defaults to true.
* `UrlbarInput` sets this property when it starts a query. If the event that started the query is a paste event and the pasted string's length is larger than maxChars, then don't allow suggestions. Otherwise do.
* `UrlbarProviderSearchSuggestions.isActive` returns false when `!context.allowSearchSuggestions`.
* `UrlbarProviderSearchSuggestions` doesn't truncate the query anymore.
* Keep the `browser.urlbar.maxCharsForSearchSuggestions` pref but use it only for pastes, and increase it from 20 to 100. I considered making a new pref but this way if a user changed it, then it still applies to pastes at least. I'm not sure it's important though.
Differential Revision: https://phabricator.services.mozilla.com/D70956
f369e0990b