Fixing Kohya loras loading: Flux.1-dev loras with TE ("lora_te1_" prefix)

[christopher5106]

Text encoder lora layers are dropped for some loras such as this one
A log message confirms it:
No LoRA keys associated to CLIPTextModel found with the prefix='text_encoder'. This is safe to ignore if LoRA state dict didn't originally have any CLIPTextModel related params. You can also try specifying prefix=None to resolve the warning. Otherwise, open an issue if you think it's unexpected: https://github.com/huggingface/diffusers/issues/new
At least, this PR brings more consistency (wherever there is lora_te_, there should be also lora_te1_)

Closes #12053

Reproducers:

FLUX.1 Dev

import torch
from diffusers import FluxPipeline

pipe = FluxPipeline.from_pretrained(
    "black-forest-labs/FLUX.1-dev", torch_dtype=torch.bfloat16
)

pipe.load_lora_weights(
    "scenario-labs/kohya-sd-scripts-loras", weight_name="flux_lora.safetensors",
)

FLUX.1 Kontext

import torch
from diffusers import FluxKontextPipeline

pipe = FluxKontextPipeline.from_pretrained(
    "black-forest-labs/FLUX.1-Kontext-dev", torch_dtype=torch.bfloat16
)

pipe.load_lora_weights(
    "scenario-labs/big-head-kontext-lora", weight_name="flux_kontext_lora.safetensors",
)

The Loras have been trained with Kohya/sd-scripts framework.
With the fix of this PR, the warning message disappears, solving the drop of layers for the text encoder.

@sayakpaul

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