Include the 'has_FIELD?' methods in RBIs generated from protobuf

[tgwizard]

Motivation

Optional fields may not be present in the serialized payload. The regular accessors will still return the default value for that field type (e.g. 0 or ""). Sometimes you want to know the difference between "default value" and "present in payload", and the has_FIELD? methods are there for that:

https://protobuf.dev/reference/ruby/ruby-generated/#checking-presence

The return type is pretty weird - it's false for when the field isn't present, and 0 for when it is.

irb(main):015> u = ShopApp::Protobuf::ServiceApi::V1::User.new
=> <ShopApp::Protobuf::ServiceApi::V1::User: id: 0, uuid: "", email_verified: false>
irb(main):016> u.email
=> ""
irb(main):017> u.has_email?
=> false
irb(main):018> u.email = "buffy@example.com"
=> "buffy@example.com"
irb(main):019> u.has_email?
=> 0
irb(main):020> u.email
=> "buffy@example.com"
irb(main):021> u.clear_email
=> nil
irb(main):022> u.has_email?
=> false

Implementation

Define the has_FIELD? method for all fields that are optional.

Tests

There are tests.

[tgwizard]

The failing CI is because something that seems unrelated:

cli
  gem
    generate
      it eagerly loads autoloaded constants                           PASS (3.37s)
      it uses ignores `abort` and `exit` calls inside autoloaded files PASS (5.98s)
      it must generate a gem RBI with the ones exported from the gem by default PASS (1.84s)
      it must respect include-dependencies option                     FAIL (7.29s)
        Expected false to be truthy.
        /home/runner/work/tapioca/tapioca/spec/spec_with_project.rb:98:in `assert_project_file_exist'
        /home/runner/work/tapioca/tapioca/spec/tapioca/cli/gem_spec.rb:[79](https://github.com/Shopify/tapioca/actions/runs/8388995127/job/22974281768?pr=1835#step:6:80)2:in `block (3 levels) in <class:GemSpec>'

[paracycle]

Thank you, this is an important omission to address. I have a few comments/questions before we can merge this, though.

[paracycle]

Awesome, thanks for the changes. This looks great now! Thanks again for the contribution.

[paracycle]

I don't know what's up with the tests, but I'll merge this since they don't seem to be related at all.