add callback after_extra_networks_activate

[w-e-w]

Description

this mainly affected extensions that needs to modify extra network after it's been activated such as lora block weights and in my opinion the actual solution to the issue that https://github.com/AUTOMATIC1111/stable-diffusion-webui/pull/11477 describes quote

this has affected several scripts, particularly causing issues in relation to LoRA

the following is mostly a repost of my Discord message on this topic

we might need to add a an extra process_batch or a new call back for hi-pass https://github.com/AUTOMATIC1111/stable-diffusion-webui/discussions/10944

I propose to add a new callback in extra_network.activate, a post extra_network_activate callback I think this is the best place to add operations that need to happen after activation of extra network but before setup_conds() normally for img2img process_batch is enough but the issue is that for txt2img with hirse-fix there are multiple activations of extra networks extensions that need to inject themselves between extra network activation and conds shoud switch to use the new call back

the key difference between process_batch only proposed new callback post_extra_network_activate is that process_batch called only once per batch whiles post_extra_network_activate maybe called multiple times (when hires-fix)

also some extensions actually activate after networks for ther own use example https://github.com/pkuliyi2015/multidiffusion-upscaler-for-automatic1111/blob/main/tile_methods/multidiffusion.py#L206

if the this call back is implemented process_batch should be moved after conds and they can be a minor optimization for conds calculation for --lowvram mode which would also entail moving scripts.process_batch after conds this would cause a breaking change this is not implemented in this PR this can be implemented later after this PR has been merged and those extension that would be affected has time to migrate to the new callback, making the migration more smooth

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