Fix(l10n): Update translations from Transifex

Signed-off-by: Nextcloud bot <bot@nextcloud.com>

l10n/is.js

@@ -1,6 +1,7 @@
 OC.L10N.register(
     "files_rightclick",
     {
+    "Unselect all" : "Afvelja allt",
     "Select" : "Velja",
     "Copied !" : "Afritað!",
     "Right click" : "Hægrismella",

l10n/is.json

@@ -1,4 +1,5 @@
 { "translations": {
+    "Unselect all" : "Afvelja allt",
     "Select" : "Velja",
     "Copied !" : "Afritað!",
     "Right click" : "Hægrismella",