Model + API: Migrate to use BaseSamplerParams

kwargs is pretty ugly when figuring out which arguments to use. The
base requests falls back to defaults anyways, so pass in the params
object as is.

However, since Python's typing isn't like TypeScript where types
can be transformed, the type hinting has a possiblity of None showing
up despite there always being a value for some params.

Signed-off-by: kingbri <8082010+kingbri1@users.noreply.github.com>

common/sampling.py

@@ -282,6 +282,11 @@ class BaseSamplerRequest(BaseModel):
         ge=0,
     )
 
+    logprobs: Optional[int] = Field(
+        default_factory=lambda: get_default_sampler_value("logprobs", 0),
+        ge=0,
+    )
+
     @field_validator("top_k", mode="before")
     def convert_top_k(cls, v):
         """Fixes instance if Top-K is -1."""