[Bug]: WebUI doesn't start using default requirements

### Checklist

- [X] The issue exists after disabling all extensions
- [X] The issue exists on a clean installation of webui
- [ ] The issue is caused by an extension, but I believe it is caused by a bug in the webui
- [ ] The issue exists in the current version of the webui
- [X] The issue has not been reported before recently
- [X] The issue has been reported before but has not been fixed yet

### What happened?

there is no pydantic==1.10.11 on my installation of WebUI Forge. Also there exists a script for xformers that doesn't install xformers on default.

### Steps to reproduce the problem

1. start Webui-user.bat
2. get Error message
3. (fix) add --xformers to webui-user.bat
4. (fix) activate venv enviroment and install with pip "pip install pydantic==1.10.11"
5. Launches successfully

### What should have happened?

WebUI should have installed the packages automatically and launched without error

### What browsers do you use to access the UI ?

Microsoft Edge

### Sysinfo

[sysinfo-2024-06-01-10-22.json](https://github.com/user-attachments/files/15521328/sysinfo-2024-06-01-10-22.json)

### Console logs

```Shell
venv "D:\AI\1.stable-diffusion-webui-forge\venv\Scripts\Python.exe"
Python 3.10.13 | packaged by Anaconda, Inc. | (main, Sep 11 2023, 13:24:38) [MSC v.1916 64 bit (AMD64)]
Version: f0.0.17v1.8.0rc-latest-276-g29be1da7
Commit hash: 29be1da7cf2b5dccfc70fbdd33eb35c56a31ffb7
Launching Web UI with arguments: --xformers --ckpt-dir D:AI1.Automatic1111modelsStable-diffusion --hypernetwork-dir D:AI1.Automatic1111modelshypernetworks --embeddings-dir D:AI1.Automatic1111embeddings --lora-dir D:AI1.Automatic1111modelsLora
Total VRAM 8192 MB, total RAM 32604 MB
WARNING:xformers:A matching Triton is not available, some optimizations will not be enabled.
Error caught was: No module named 'triton'
xformers version: 0.0.23.post1
Set vram state to: NORMAL_VRAM
Device: cuda:0 NVIDIA GeForce RTX 3070 Ti : native
Hint: your device supports --pin-shared-memory for potential speed improvements.
Hint: your device supports --cuda-malloc for potential speed improvements.
Hint: your device supports --cuda-stream for potential speed improvements.
VAE dtype: torch.bfloat16
CUDA Stream Activated: False
Traceback (most recent call last):
File "D:\AI\1.stable-diffusion-webui-forge\launch.py", line 51, in
main()
File "D:\AI\1.stable-diffusion-webui-forge\launch.py", line 47, in main
start()
File "D:\AI\1.stable-diffusion-webui-forge\modules\launch_utils.py", line 541, in start
import webui
File "D:\AI\1.stable-diffusion-webui-forge\webui.py", line 19, in
initialize.imports()
File "D:\AI\1.stable-diffusion-webui-forge\modules\initialize.py", line 35, in imports
import gradio # noqa: F401
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\gradio\__init__.py", line 3, in
import gradio.components as components
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\gradio\components\__init__.py", line 1, in
from gradio.components.annotated_image import AnnotatedImage
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\gradio\components\annotated_image.py", line 13, in
from gradio.components.base import IOComponent, _Keywords
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\gradio\components\base.py", line 20, in
from fastapi import UploadFile
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\fastapi\__init__.py", line 7, in
from .applications import FastAPI as FastAPI
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\fastapi\applications.py", line 15, in
from fastapi import routing
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\fastapi\routing.py", line 22, in
from fastapi import params
File "D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\fastapi\params.py", line 4, in
from pydantic.fields import FieldInfo, Undefined
ImportError: cannot import name 'Undefined' from 'pydantic.fields' (D:\AI\1.stable-diffusion-webui-forge\venv\lib\site-packages\pydantic\fields.py)
Drücken Sie eine beliebige Taste . . .
```

### Additional information

also the arguments to set a base directory of automatic1111 seem to be broken

Reproduce the failure with webui-user.bat and trace the startup path through launch.py, modules/launch_utils.py, modules/initialize.py, and webui.py. Check the dependency and argument-handling paths implicated by the pydantic, xformers, and base-directory errors. Done means a clean default installation launches without manual package installation or extra arguments.

Written by the indexing model from the issue text.