fix(gemini-embedding): wrap batch embedding texts in Content to avoid collapse on gemini-embedding-2 (#8537)

* fix(provider): wrap batch embedding texts in Content to avoid collapse on gemini-embedding-2

* fix(gemini_embedding): format list comprehension for better readability

---------

Co-authored-by: Rat0323 <Rat0323@users.noreply.github.com>
Co-authored-by: Soulter <905617992@qq.com>

astrbot/core/provider/sources/gemini_embedding_source.py

@@ -1,4 +1,3 @@
-from typing import cast
 
 from google import genai
 from google.genai import types
@@ -61,9 +60,12 @@ class GeminiEmbeddingProvider(EmbeddingProvider):
     async def get_embeddings(self, text: list[str]) -> list[list[float]]:
         """批量获取文本的嵌入"""
         try:
+            contents = [
+                types.Content(parts=[types.Part.from_text(text=s)]) for s in text
+            ]
             result = await self.client.models.embed_content(
                 model=self.model,
-                contents=cast(types.ContentListUnion, text),
+                contents=contents,
                 config=types.EmbedContentConfig(
                     output_dimensionality=self.get_dim(),
                 ),