fix: Processing negative embeddings wrong

[wpdong0727]

Description

• When checkpoint switches from SDXL to other versions such as SD1.5, what is stored in embedding_db is the textual inversion of SDXL. If the model is loaded from already_loaded, the SD1.5 generation tasks will not be able to load the correct embeddings, and vice versa.
• It is necessary to reload the textual inversion.
• This could be the cause of this issue.

Screenshots/videos:

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests

[AUTOMATIC1111]

I can't seem to reproduce the error on my side. I tried loading SD15, generating picture, loading SDXL, generating picture, and loading back to SD15 and generating picture - the generated picture matches the first one and TI hashes are present in the infotext. I also tried with persistent cond cache option on and off, and I tried starting with SDXL model already loaded - can't reproduce.

[AUTOMATIC1111]

closing due to no reply; reopen if needed.