refactor: remove assert statement from non-test files (#7029)

Usage of `assert` statement in application logic is discouraged.
`assert` is removed with compiling to optimized byte code. Consider
raising an exception instead. Ideally, `assert` statement should be used
only in tests.

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Co-authored-by: deepsource-autofix[bot] <62050782+deepsource-autofix[bot]@users.noreply.github.com>

monai/apps/utils.py

@@ -208,7 +208,7 @@ def download_url(
                 with urlopen(url) as response:
                     code = response.getcode()
                     if code == 200:
-                        download_url = json.loads(response.read())["href"]
+                        download_url = json.load(response)["href"]
                         _download_with_progress(download_url, tmp_name, progress=progress)
                     else:
                         raise RuntimeError(

monai/networks/blocks/pos_embed_utils.py

@@ -57,7 +57,8 @@ def build_sincos_position_embedding(
 
         grid_h, grid_w = torch.meshgrid(grid_h, grid_w, indexing="ij")
 
-        assert embed_dim % 4 == 0, "Embed dimension must be divisible by 4 for 2D sin-cos position embedding"
+        if embed_dim % 4 != 0:
+            raise AssertionError("Embed dimension must be divisible by 4 for 2D sin-cos position embedding")
 
         pos_dim = embed_dim // 4
         omega = torch.arange(pos_dim, dtype=torch.float32) / pos_dim
@@ -75,7 +76,8 @@ def build_sincos_position_embedding(
 
         grid_h, grid_w, grid_d = torch.meshgrid(grid_h, grid_w, grid_d, indexing="ij")
 
-        assert embed_dim % 6 == 0, "Embed dimension must be divisible by 6 for 3D sin-cos position embedding"
+        if embed_dim % 6 != 0:
+            raise AssertionError("Embed dimension must be divisible by 6 for 3D sin-cos position embedding")
 
         pos_dim = embed_dim // 6
         omega = torch.arange(pos_dim, dtype=torch.float32) / pos_dim