Bugfix/openapispec empty tag

[anusreesubash]

``# Description

While trying to import collection as openapispec file that contains tags: "" , application throws error saying it is corrupted file
as the app cannot have folder with empty name.

This PR will move the requests with empty tags "" to ungrouped so that these requests will be created directly under the collection.

Contribution Checklist:

• The pull request only addresses one issue or adds one feature.
• The pull request does not introduce any breaking changes
• I have added screenshots or gifs to help explain the change if applicable.
• I have read the contribution guidelines.

Here is a sample open api spec that fails import in current implementation:

openapi: 3.0.0
info:
  title: User Management API
  description: API for managing users with create, read, update, and delete operations
  version: 1.0.0
servers:
  - url: https://api.example.com/v1
paths:
  /users:
    get:
      tags:
        - ""
      summary: Retrieve a list of users
      description: Get a list of all users
      responses:
        '200':
          description: A list of users
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
                  properties:
                    id:
                      type: string
                      example: "123"
                    name:
                      type: string
                      example: "John Doe"
                    email:
                      type: string
                      example: "[[email protected]](mailto:[email protected])"