Revert "[PLT-7475] Add S3 region to system console and add S3 validation (#7373)" (#7387)

This reverts commit 8d680cf64e.

Move to 4.3.
Will discuss more if validation is necessary.

webapp/components/admin_console/storage_settings.jsx

@@ -34,7 +34,6 @@ export default class StorageSettings extends AdminSettings {
         config.FileSettings.AmazonS3AccessKeyId = this.state.amazonS3AccessKeyId;
         config.FileSettings.AmazonS3SecretAccessKey = this.state.amazonS3SecretAccessKey;
         config.FileSettings.AmazonS3Bucket = this.state.amazonS3Bucket;
-        config.FileSettings.AmazonS3Region = this.state.amazonS3Region;
         config.FileSettings.AmazonS3Endpoint = this.state.amazonS3Endpoint;
         config.FileSettings.AmazonS3SSL = this.state.amazonS3SSL;
         config.FileSettings.AmazonS3SSE = this.state.amazonS3SSE;
@@ -54,7 +53,6 @@ export default class StorageSettings extends AdminSettings {
             amazonS3AccessKeyId: config.FileSettings.AmazonS3AccessKeyId,
             amazonS3SecretAccessKey: config.FileSettings.AmazonS3SecretAccessKey,
             amazonS3Bucket: config.FileSettings.AmazonS3Bucket,
-            amazonS3Region: config.FileSettings.AmazonS3Region,
             amazonS3Endpoint: config.FileSettings.AmazonS3Endpoint,
             amazonS3SSL: config.FileSettings.AmazonS3SSL,
             amazonS3SSE: config.FileSettings.AmazonS3SSE,
@@ -243,25 +241,6 @@ export default class StorageSettings extends AdminSettings {
                     onChange={this.handleChange}
                     disabled={this.state.driverName !== DRIVER_S3}
                 />
-                <TextSetting
-                    id='amazonS3Region'
-                    label={
-                        <FormattedMessage
-                            id='admin.image.amazonS3RegionTitle'
-                            defaultMessage='Amazon S3 Region:'
-                        />
-                    }
-                    placeholder={Utils.localizeMessage('admin.image.amazonS3RegionExample', 'Ex "us-east-1"')}
-                    helpText={
-                        <FormattedMessage
-                            id='admin.image.amazonS3RegionDescription'
-                            defaultMessage='(Optional) AWS region you selected when creating your S3 bucket. If no region is set, Mattermost attempts to get the appropriate region from AWS, or sets it to "us-east-1" if none found.'
-                        />
-                    }
-                    value={this.state.amazonS3Region}
-                    onChange={this.handleChange}
-                    disabled={this.state.driverName !== DRIVER_S3}
-                />
                 <TextSetting
                     id='amazonS3Endpoint'
                     label={