Remove HTML breaks from browser warning strings (#78)

They're not required anymore since we now have a max-width property on all dialogs.

public/i18n/de.json

@@ -1,7 +1,7 @@
 {
     "welcome": {
         "ABORT": "Abbrechen",
-        "BROWSER_NOT_SUPPORTED_DETAILS": "Bitte verwenden Sie die aktuelle Version von <a href='https:\/\/www.google.com\/chrome\/browser\/desktop\/' target='_blank' rel='noopener noreferrer'>Google Chrome<\/a> oder <a href='https:\/\/www.mozilla.org\/' target='_blank' rel='noopener noreferrer'>Mozilla Firefox<\/a>,<br>um den Webclient ohne Einschr\u00e4nkungen zu nutzen.",
+        "BROWSER_NOT_SUPPORTED_DETAILS": "Bitte verwenden Sie die aktuelle Version von <a href='https:\/\/www.google.com\/chrome\/browser\/desktop\/' target='_blank' rel='noopener noreferrer'>Google Chrome<\/a> oder <a href='https:\/\/www.mozilla.org\/' target='_blank' rel='noopener noreferrer'>Mozilla Firefox<\/a>, um den Webclient ohne Einschr\u00e4nkungen zu nutzen.",
         "CONTINUE_ANYWAY": "Trotzdem fortfahren",
         "PLEASE_SCAN": "Scannen Sie den QR-Code mit Ihrer Threema-App",
         "PLEASE_UNLOCK": "Verbindung wiederaufbauen",

public/i18n/en.json

@@ -1,7 +1,7 @@
 {
     "welcome": {
         "ABORT": "Abort",
-        "BROWSER_NOT_SUPPORTED_DETAILS": "Please use the latest version of <a href='https:\/\/www.google.com\/chrome\/browser\/desktop\/' target='_blank' rel='noopener noreferrer'>Google Chrome<\/a> or <a href='https:\/\/www.mozilla.org\/' target='_blank' rel='noopener noreferrer'>Mozilla Firefox<\/a>,<br>otherwise the web client might not work properly.",
+        "BROWSER_NOT_SUPPORTED_DETAILS": "Please use the latest version of <a href='https:\/\/www.google.com\/chrome\/browser\/desktop\/' target='_blank' rel='noopener noreferrer'>Google Chrome<\/a> or <a href='https:\/\/www.mozilla.org\/' target='_blank' rel='noopener noreferrer'>Mozilla Firefox<\/a>, otherwise the web client might not work properly.",
         "CONTINUE_ANYWAY": "Continue anyway",
         "PLEASE_SCAN": "Scan this QR code with your Threema app",
         "PLEASE_UNLOCK": "Reconnecting session",