Chore: remove unattached JH msgids

What does this MR do and why?

1. Sort po files.
2. Remove unattached msgids， which are not found both in JH and upstream.

Screenshots or screen recordings

How to set up and validate locally

1. Save two versions of a po file, such as left.po and right.po
2. Run ruby compare.rb left.po right.po
3. You should see the po files are matched.

compare.rb

require 'rubygems'
require 'active_support/all'
require 'gettext/po_parser'


def po_parse(file)
  parser = GetText::POParser.new
  parser.ignore_fuzzy = true

  parser.parse_file(file, GetText::PO.new).index_by(&:msgid)
end

left = po_parse(ARGF.argv[0])
right = po_parse(ARGF.argv[1])

left.each do |key, entry|
  raise "#{key} not found" if !right.key?(key) || entry.to_s != right[key].to_s
end

p "#{left.count} entries are matched !"

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Closes #1116 (closed)