Update base for Update on "[3/N] Add get_option/set_option function in backend interface"

Add update function in backend interface class. The update function will receive the backend options from dispatched by the ET runtime.

ET runtime's logic: loop over each backend and it's corresponding backend options, dispatch the backend options to the corresponding backend

Next step, will add update API in the method and then module
exported-using-ghexport

Differential Revision: [D75919242](https://our.internmc.facebook.com/intern/diff/D75919242/)

Differential Revision: [D75919242](https://our.internmc.facebook.com/intern/diff/D75919242)

[ghstack-poisoned]

Author: cccclai

runtime/backend/options.h

@@ -29,7 +29,7 @@ using OptionValue =
 struct BackendOption {
   // key is the name of the backend option, like num_threads, enable_profiling,
   // etc
-  char key[kMaxOptionKeyLength];
+  char key[kMaxOptionKeyLength]{};
   // value is the value of the backend option, like 4, true, etc
   OptionValue value;
 };
@@ -129,7 +129,7 @@ class BackendOptions {
   Error set_option(const char (&key)[N], const char* value) noexcept {
     static_assert(N <= kMaxOptionKeyLength, "Option key is too long");
     // Create a fixed-size array and copy the string
-    std::array<char, kMaxOptionValueLength> arr;
+    std::array<char, kMaxOptionValueLength> arr{};
     strncpy(arr.data(), value, kMaxOptionValueLength - 1);
     arr[kMaxOptionValueLength - 1] = '\0'; // Ensure null termination
     return set_option_impl(key, arr);