chore: enforce 16 characters for invidious_companion_key (iv-org#5220)

Author: unixfox

src/invidious/config.cr

@@ -271,8 +271,8 @@ class Config
       elsif config.invidious_companion_key == "CHANGE_ME!!"
         puts "Config: The value of 'invidious_companion_key' needs to be changed!!"
         exit(1)
-      elsif config.invidious_companion_key.size < 16
-        puts "Config: The value of 'invidious_companion_key' needs to be a size of 16 or more."
+      elsif config.invidious_companion_key.size != 16
+        puts "Config: The value of 'invidious_companion_key' needs to be a size of 16 characters."
         exit(1)
       end
     elsif config.signature_server