Fix integer overflow in cJSON_GetArraySize by using size_t

[Will-gabia]

This PR addresses a potential integer overflow in cJSON_GetArraySize where returning an int for arrays larger than INT_MAX would cause truncation or overflow.

Changes:

• Modified cJSON_GetArraySize in src/cJSON.c and src/include/switch_cJSON.h to return size_t.
• Updated array manipulation functions (cJSON_GetArrayItem, cJSON_DetachItemFromArray, cJSON_DeleteItemFromArray, cJSON_InsertItemInArray, cJSON_ReplaceItemInArray) to accept size_t for the index parameter. This ensures that large arrays can be accessed and manipulated correctly.
• Removed redundant checks for negative indices since size_t is unsigned.

Verification:

• Created a C test file to verify basic array operations (add, get size, get item, delete, insert, replace) with the new signatures.
• Verified that passing negative values (wrapping to large size_t) results in safe behavior (NULL return for Get/Detach, append for Insert) consistent with the library's safety mechanisms.

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PR created automatically by Jules for task 2124603859890423596 started by @Will-gabia

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