fix(apps/nuclick): replace np.random.choice with self.R.choice in Add… (#8836)

Fixes #6888 (partial) - follow-up to #8798

### Description

In `AddPointGuidanceSignald.exclusion_map`
(`monai/apps/nuclick/transforms.py`), two calls used `np.random.choice`
(global NumPy random state) instead of `self.R.choice`. Since
`AddPointGuidanceSignald` already inherits from `Randomizable`, this is
a straightforward replacement that ensures reproducibility when
`set_determinism()` or manual seeding is used.

**Before:**
```python
if np.random.choice([True, False], p=[drop_rate, 1 - drop_rate]):
```

**After:**
```python
if self.R.choice([True, False], p=[drop_rate, 1 - drop_rate]):
```

PR #8798 already fixed `np.random.*` calls in transforms and data
utilities. This PR continues that work for the two remaining calls in
`apps/nuclick/transforms.py` mentioned in #6888.

### Types of changes
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [ ] Breaking change (fix or new feature that would cause existing
functionality to change).
- [ ] New tests added to cover the changes.
- [ ] Integration tests passed locally by running `./runtests.sh -f -u
--net --coverage`.
- [ ] Quick tests passed locally by running `./runtests.sh --quick
--unittests --disttests`.
- [ ] In-line docstrings updated.
- [ ] Documentation updated, tested `make html` command in the `docs/`
folder.

Signed-off-by: Zeeshan Modi <92383127+Zeesejo@users.noreply.github.com>

Author: Zeesejo

monai/apps/nuclick/transforms.py

@@ -367,14 +367,14 @@ def inclusion_map(self, mask, dtype):
 
     def exclusion_map(self, others, dtype, jitter_range, drop_rate):
         point_mask = torch.zeros_like(others, dtype=dtype)
-        if np.random.choice([True, False], p=[drop_rate, 1 - drop_rate]):
+        if self.R.choice([True, False], p=[drop_rate, 1 - drop_rate]):
             return point_mask
 
         max_x = point_mask.shape[0] - 1
         max_y = point_mask.shape[1] - 1
         stats = measure.regionprops(convert_to_numpy(others))
         for stat in stats:
-            if np.random.choice([True, False], p=[drop_rate, 1 - drop_rate]):
+            if self.R.choice([True, False], p=[drop_rate, 1 - drop_rate]):
                 continue
 
             # random jitter