Removed i18n dependency from yaml parser module

refs https://linear.app/tryghost/issue/CORE-35/refactor-route-and-redirect-settings

- i18n is an old pattern we are getting rid of. By removing it here we get rid of an extra dependancy on frontend's "proxy" module

core/frontend/services/settings/yaml-parser.js

@@ -1,8 +1,15 @@
 const yaml = require('js-yaml');
 const debug = require('@tryghost/debug')('frontend:services:settings:yaml-parser');
-const {i18n} = require('../proxy');
+const tpl = require('@tryghost/tpl');
 const errors = require('@tryghost/errors');
 
+const messages = {
+    yamlParsing: {
+        error: 'Could not parse {file}: {context}.',
+        help: 'Check your {file} file for typos and fix the named issues.'
+    }
+};
+
 /**
  * Takes a YAML file, parses it and returns a JSON Object
  * @param {YAML} file the YAML file utf8 encoded
@@ -21,11 +28,11 @@ module.exports = function parseYaml(file, fileName) {
         // `reason` property as well as in the message.
         // As the file uploaded is invalid, the person uploading must fix this - it's a 4xx error
         throw new errors.IncorrectUsageError({
-            message: i18n.t('errors.services.settings.yaml.error', {file: fileName, context: error.reason}),
+            message: tpl(messages.yamlParsing.error, {file: fileName, context: error.reason}),
             code: 'YAML_PARSER_ERROR',
             context: error.message,
             err: error,
-            help: i18n.t('errors.services.settings.yaml.help', {file: fileName})
+            help: tpl(messages.yamlParsing.help, {file: fileName})
         });
     }
 };

core/shared/i18n/translations/en.json

@@ -541,8 +541,6 @@
         "services": {
             "settings": {
                 "yaml": {
-                    "error": "Could not parse {file}: {context}.",
-                    "help": "Check your {file} file for typos and fix the named issues.",
                     "validate": "The following definition \"{at}\" is invalid: {reason}"
                 }
             },