Allow conan_export file for Conan uploads

The conan_export.tgz file is allowed as a
valid file for conan uploads.

changelogs/unreleased/210550-conan-export-tgz.yml

+---
+title: Conan package registry support for the conan_export.tgz file
+merge_request: 32866
+author:
+type: fixed

ee/app/models/packages/conan/file_metadatum.rb

@@ -18,7 +18,7 @@ class Packages::Conan::FileMetadatum < ApplicationRecord
 
   enum conan_file_type: { recipe_file: 1, package_file: 2 }
 
-  RECIPE_FILES = %w[conanfile.py conanmanifest.txt conan_sources.tgz].freeze
+  RECIPE_FILES = %w[conanfile.py conanmanifest.txt conan_sources.tgz conan_export.tgz].freeze
   PACKAGE_FILES = %w[conaninfo.txt conanmanifest.txt conan_package.tgz].freeze
   PACKAGE_BINARY = 'conan_package.tgz'
 

ee/spec/requests/api/conan_packages_spec.rb

@@ -420,7 +420,8 @@ describe API::ConanPackages do
       let(:params) do
         { "conanfile.py": 24,
           "conanmanifext.txt": 123,
-          "conan_sources.tgz": 523 }
+          "conan_sources.tgz": 523,
+          "conan_export.tgz": 432 }
       end
 
       subject { post api("/packages/conan/v1/conans/#{recipe_path}/upload_urls"), params: params, headers: headers }
@@ -433,7 +434,8 @@ describe API::ConanPackages do
         expected_response = {
           'conanfile.py':      "#{Settings.gitlab.base_url}/api/v4/packages/conan/v1/files/#{package.conan_recipe_path}/0/export/conanfile.py",
           'conanmanifest.txt': "#{Settings.gitlab.base_url}/api/v4/packages/conan/v1/files/#{package.conan_recipe_path}/0/export/conanmanifest.txt",
-          'conan_sources.tgz': "#{Settings.gitlab.base_url}/api/v4/packages/conan/v1/files/#{package.conan_recipe_path}/0/export/conan_sources.tgz"
+          'conan_sources.tgz': "#{Settings.gitlab.base_url}/api/v4/packages/conan/v1/files/#{package.conan_recipe_path}/0/export/conan_sources.tgz",
+          'conan_export.tgz': "#{Settings.gitlab.base_url}/api/v4/packages/conan/v1/files/#{package.conan_recipe_path}/0/export/conan_export.tgz"
         }
 
         expect(response.body).to eq(expected_response.to_json)