Don't cache script-injection state when a page already has scripts

injectTranslationScripts() returned before its cleanup when a ping showed
the scripts were already present, permanently caching the per-tab
in-progress marker, so all later calls for the tab returned the cached
promise without pinging or injecting. Chromium and Firefox inject content
scripts on every page, so the skipped injection didn't matter there, but
on Safari a tab can reach a page without scripts, e.g., by navigating to
an ungranted site that the user then grants access to, and the on-demand
injection for user actions would silently do nothing for the rest of the
tab's life. Run the cleanup on every path.

Author: dstillman

src/browserExt/background.js

@@ -356,12 +356,12 @@ Zotero.Connector_Browser = new function() {
 		}
 		deferred = Zotero.Promise.defer();
 		this.injectTranslationScripts[key] = deferred;
-		
-		let response = await Zotero.Messaging.sendMessage('ping', null, tab, frameId)
-		if (response && frameId == 0) return deferred.resolve();
-		url = url ? `${url} - ${tab.url}` : tab.url
-		Zotero.debug(`Injecting translation scripts into ${frameId} ${url}`);
+
 		try {
+			let response = await Zotero.Messaging.sendMessage('ping', null, tab, frameId)
+			if (response && frameId == 0) return deferred.resolve();
+			url = url ? `${url} - ${tab.url}` : tab.url
+			Zotero.debug(`Injecting translation scripts into ${frameId} ${url}`);
 			return await Zotero.Connector_Browser.injectScripts(_injectTranslationScripts, tab, frameId);
 		} catch (e) {
 			Zotero.debug(`Translation Inject: Script injection rejected ${key}`);