Initialize variables (#18682)

### Ticket
N/A

### Problem description
Need to initialize variables to ensure consistent behaviour

### What's changed
Set them to false as the kernels haven't been found yet from
dynamic_cast

### Checklist
- [ ] [All post
commit](https://github.com/tenstorrent/tt-metal/actions/workflows/all-post-commit-workflows.yaml)
CI passes
- [ ] [Blackhole Post
commit](https://github.com/tenstorrent/tt-metal/actions/workflows/blackhole-post-commit.yaml)
CI passes (if applicable)
- [ ] [Model
regression](https://github.com/tenstorrent/tt-metal/actions/workflows/perf-models.yaml)
CI passes (if applicable)
- [ ] [Device performance
regression](https://github.com/tenstorrent/tt-metal/actions/workflows/perf-device-models.yaml)
CI passes (if applicable)
- [ ] **(For models and ops writers)** Full [new models
tests](https://github.com/tenstorrent/tt-metal/actions/workflows/full-new-models-suite.yaml)
CI passes (if applicable)
- [ ] New/Existing tests provide coverage for changes

tt_metal/impl/dispatch/kernel_config/dispatch.cpp

@@ -271,9 +271,9 @@ void DispatchKernel::GenerateDependentConfigs() {
         auto dispatch_s_kernel = dynamic_cast<DispatchSKernel*>(downstream_kernels_[0]);
         auto mux_kernel = dynamic_cast<MuxKernel*>(downstream_kernels_[0]);
 
-        bool found_dispatch_s;
-        bool found_mux;
-        bool found_dispatch_h;
+        bool found_dispatch_s = false;
+        bool found_mux = false;
+        bool found_dispatch_h = false;
         for (auto ds_kernel : downstream_kernels_) {
             if (auto dispatch_s_kernel = dynamic_cast<DispatchSKernel*>(ds_kernel)) {
                 dependent_config_.downstream_s_logical_core = dispatch_s_kernel->GetLogicalCore();