Update on "[5.1/ N] set_option/get_option API with {backend_name, backend options} only"

This PR only expose the set_option/get_option API via the pair {backend_name, backend_options}, without necessarily backend options map. The backend options map and it's corresponding API will be exposed to another PR

Reference PR in #11758 which exposes the set_option/get_option with backendoptions map too

Differential Revision: [D77190316](https://our.internmc.facebook.com/intern/diff/D77190316/)

[ghstack-poisoned]

Author: cccclai

runtime/backend/options.h

@@ -92,7 +92,7 @@ class BackendOptions {
    * @param value The boolean value to set
    * @return Error::Ok on success, Error::InvalidArgument if storage is full
    */
-  Error set_option(const char* key, bool value) noexcept {
+  Error set_option(const char key[kMaxOptionKeyLength], bool value) noexcept {
     ET_CHECK_MSG(
         strlen(key) <= kMaxOptionKeyLength,
         "Option key %s (%zu) is too long (max %zu)",
@@ -111,7 +111,7 @@ class BackendOptions {
    * @param value The integer value to set
    * @return Error::Ok on success, Error::InvalidArgument if storage is full
    */
-  Error set_option(const char* key, int value) noexcept {
+  Error set_option(const char key[kMaxOptionKeyLength], int value) noexcept {
     ET_CHECK_MSG(
         strlen(key) <= kMaxOptionKeyLength,
         "Option key %s (%zu) is too long (max %zu)",
@@ -133,13 +133,14 @@ class BackendOptions {
    * @param value The string value to set (must have static storage duration)
    * @return Error::Ok on success, Error::InvalidArgument if storage is full
    */
-  Error set_option(const char* key, const char* value) noexcept {
+  Error set_option(const char key[kMaxOptionKeyLength], const char* value) noexcept {
     ET_CHECK_MSG(
         strlen(key) <= kMaxOptionKeyLength,
         "Option key %s (%zu) is too long (max %zu)",
         key,
         strlen(key),
         kMaxOptionKeyLength);
+
     // Create a fixed-size array and copy the string
     std::array<char, kMaxOptionValueLength> arr;
     strncpy(arr.data(), value, kMaxOptionValueLength - 1);
@@ -158,7 +159,7 @@ class BackendOptions {
    */
   template <typename T, size_t KeyLen>
   Error get_option(const char (&key)[KeyLen], T& out) const {
-    static_assert(KeyLen <= kMaxOptionKeyLength, "Option key is too long");
+    ET_CHECK_MSG(KeyLen <= kMaxOptionKeyLength, "Option key is too long");
     for (size_t i = 0; i < size_; ++i) {
       if (std::strcmp(options_[i].key, key) == 0) {
         // Special handling for string (convert array to const char*)