fix(battery): Crash when format-low not defined

This was a backwards-incompatible change introduced in #2199, however it
was caused because `module_formatter.has` throws an exception when the
format doesn't exist instead of just returning false.

Fixes #2262
Ref #2199

src/modules/meta/base.cpp

@@ -152,7 +152,7 @@ namespace modules {
   bool module_formatter::has(const string& tag, const string& format_name) {
     auto format = m_formats.find(format_name);
     if (format == m_formats.end()) {
-      throw undefined_format(format_name);
+      return false;
     }
     return format->second->value.find(tag) != string::npos;
   }