Put the 'decrypting' tooltip back (#30446)

...when downloading encrypted attachments (regressed by https://github.com/element-hq/element-web/pull/30330).

Also adds tests for the tooltips and fix the tests so they don't pollute
mocks / dialogs.

src/components/views/messages/DownloadActionButton.tsx

@@ -26,6 +26,12 @@ interface IProps {
     mediaEventHelperGet: () => MediaEventHelper | undefined;
 }
 
+function useButtonTitle(loading: boolean, isEncrypted: boolean): string {
+    if (!loading) return _t("action|download");
+
+    return isEncrypted ? _t("timeline|download_action_decrypting") : _t("timeline|download_action_downloading");
+}
+
 export default function DownloadActionButton({ mxEvent, mediaEventHelperGet }: IProps): ReactElement | null {
     const mediaEventHelper = useMemo(() => mediaEventHelperGet(), [mediaEventHelperGet]);
     const downloadUrl = mediaEventHelper?.media.srcHttp ?? "";
@@ -33,6 +39,8 @@ export default function DownloadActionButton({ mxEvent, mediaEventHelperGet }: I
 
     const { download, loading, canDownload } = useDownloadMedia(downloadUrl, fileName, mxEvent);
 
+    const buttonTitle = useButtonTitle(loading, mediaEventHelper?.media.isEncrypted ?? false);
+
     if (!canDownload) return null;
 
     const spinner = loading ? <Spinner w={18} h={18} /> : undefined;
@@ -45,7 +53,7 @@ export default function DownloadActionButton({ mxEvent, mediaEventHelperGet }: I
     return (
         <RovingAccessibleButton
             className={classes}
-            title={loading ? _t("timeline|download_action_downloading") : _t("action|download")}
+            title={buttonTitle}
             onClick={download}
             disabled={loading}
             placement="left"

src/i18n/strings/en_EN.json

@@ -3373,6 +3373,7 @@
             "unable_to_decrypt": "Unable to decrypt message"
         },
         "disambiguated_profile": "%(displayName)s (%(matrixId)s)",
+        "download_action_decrypting": "Decrypting",
         "download_action_downloading": "Downloading",
         "download_failed": "Download failed",
         "download_failed_description": "An error occurred while downloading this file",