Fix sigmoid operator to support boolean tensor inputs (#13515)

This PR fixes the issue where boolean tensors were rejected by the
`sigmoid` operator in ExecuTorch.
Specifically, it removes the rejection check for boolean tensors in
`op_sigmoid.cpp` and adds proper conversion logic:

* `true` → `1.0` → `sigmoid(1.0) ≈ 0.731059`
* `false` → `0.0` → `sigmoid(0.0) = 0.5`

This resolves the failure reported in **#13492**, where a boolean tensor
with shape `(4, 7, 1, 1, 7, 2)` could not be processed by
`sigmoid.default`.

### Changes

* Removed boolean rejection check in `op_sigmoid.cpp`.
* Added boolean-to-float conversion logic (`true -> 1.0`, `false ->
0.0`) before applying sigmoid.
* Added comprehensive boolean tensor tests in `op_sigmoid_test.cpp`.

### Fixes

Fixes #13492 

### Test Plan

* Added new unit tests in `op_sigmoid_test.cpp` to validate behavior
with boolean tensors.
* Verified that boolean tensors now produce correct sigmoid outputs
without rejection.

Author: notkisk

kernels/portable/cpu/op_sigmoid.cpp

@@ -21,8 +21,6 @@ using Tensor = executorch::aten::Tensor;
 Tensor& sigmoid_out(KernelRuntimeContext& ctx, const Tensor& in, Tensor& out) {
   (void)ctx;
 
-  ET_KERNEL_CHECK(
-      ctx, in.scalar_type() != ScalarType::Bool, InvalidArgument, out);
   ET_KERNEL_CHECK(ctx, tensor_is_floating_type(out), InvalidArgument, out);
 
   ET_KERNEL_CHECK(

kernels/test/op_sigmoid_test.cpp

@@ -35,7 +35,6 @@ class OpSigmoidOutTest : public OperatorTest {
 
     const std::vector<int32_t> sizes = {2, 2};
 
-    // Destination for the sigmoid operator.
     Tensor out = tf_out.zeros(sizes);
 
     op_sigmoid_out(tf.make(sizes, /*data=*/{1, 2, 4, 8}), out);
@@ -50,6 +49,30 @@ class OpSigmoidOutTest : public OperatorTest {
     EXPECT_TENSOR_CLOSE(out, tf_out.full({18}, 0.880797));
   }
 
+  // Test boolean tensor support
+  template <ScalarType OUTPUT_DTYPE>
+  void test_boolean_sigmoid_out() {
+    TensorFactory<ScalarType::Bool> tf;
+    TensorFactory<OUTPUT_DTYPE> tf_out;
+
+    const std::vector<int32_t> sizes = {2, 2};
+
+    Tensor out = tf_out.zeros(sizes);
+
+    op_sigmoid_out(tf.make(sizes, /*data=*/{true, false, true, false}), out);
+
+    EXPECT_TENSOR_CLOSE(
+        out, tf_out.make(sizes, /*data=*/{0.731059, 0.5, 0.731059, 0.5}));
+
+    out = tf_out.zeros({3});
+    op_sigmoid_out(tf.make({3}, /*data=*/{true, true, true}), out);
+    EXPECT_TENSOR_CLOSE(out, tf_out.full({3}, 0.731059));
+
+    out = tf_out.zeros({3});
+    op_sigmoid_out(tf.make({3}, /*data=*/{false, false, false}), out);
+    EXPECT_TENSOR_CLOSE(out, tf_out.full({3}, 0.5));
+  }
+
   // Unhandled output dtypes.
   template <ScalarType OUTPUT_DTYPE>
   void test_sigmoid_invalid_output_dtype_dies() {
@@ -89,6 +112,16 @@ TEST_F(OpSigmoidOutTest, AllRealInputDoubleOutputSupport) {
 #undef TEST_ENTRY
 }
 
+// Test boolean tensor support with float output
+TEST_F(OpSigmoidOutTest, BooleanInputFloatOutputSupport) {
+  test_boolean_sigmoid_out<ScalarType::Float>();
+}
+
+// Test boolean tensor support with double output
+TEST_F(OpSigmoidOutTest, BooleanInputDoubleOutputSupport) {
+  test_boolean_sigmoid_out<ScalarType::Double>();
+}
+
 // Mismatched shape tests.
 TEST_F(OpSigmoidOutTest, MismatchedShapesDies) {
   if (SupportedFeatures::get()->is_aten) {