[Bug]: ":-1" will mislead the negative prompt

[zc1023]

Is there an existing issue for this?

• [X] I have searched the existing issues and checked the recent builds/commits

What happened?

If the prompt contains "-1", the negative prompt effect will be equal to the prompt.

Steps to reproduce the problem

1. input ":-1" as prompt
2. input anything as negative prompt
3. you will find that the negative prompt's effect is equal to the prompt's

What should have happened?

I think ":-1" should not mislead the negative prompt

Commit where the problem happens

UI

What Python version are you running on ?

Python 3.10.x

What platforms do you use to access the UI ?

Linux

What device are you running WebUI on?

Nvidia GPUs (RTX 20 above)

What browsers do you use to access the UI ?

Microsoft Edge

Command Line Arguments

No

List of extensions

No

Console logs

NO

Additional information

No response