fix compile error on Linux

[regunakyle]

I tried to compile this project in Linux (Ubuntu 26 container) and got the following error:

/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/src/parser.cpp:174:32: error: call of overloaded 'JSON(long long int)' is ambiguous
  174 |       return JSON(stoll(number));
      |                                ^
/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/src/parser.cpp:174:32: note: there are 6 candidates
In file included from /workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/include/discord_ipc_cpp/parser.hpp:13,
                 from /workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/src/parser.cpp:8:
/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/include/discord_ipc_cpp/json.hpp:162:12: note: candidate 1: 'discord_ipc_cpp::json::JSON::JSON(discord_ipc_cpp::json::JSONBool)'
  162 |   explicit JSON(JSONBool value);
      |            ^~~~
/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/include/discord_ipc_cpp/json.hpp:154:12: note: candidate 2: 'discord_ipc_cpp::json::JSON::JSON(discord_ipc_cpp::json::JSONDouble)'
  154 |   explicit JSON(JSONDouble value);
      |            ^~~~
/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/include/discord_ipc_cpp/json.hpp:146:12: note: candidate 3: 'discord_ipc_cpp::json::JSON::JSON(discord_ipc_cpp::json::JSONLong)'
  146 |   explicit JSON(JSONLong value);
      |            ^~~~
/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/include/discord_ipc_cpp/json.hpp:138:12: note: candidate 4: 'discord_ipc_cpp::json::JSON::JSON(discord_ipc_cpp::json::JSONInt)'
  138 |   explicit JSON(JSONInt value);
      |            ^~~~
/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/include/discord_ipc_cpp/json.hpp:69:7: note: candidate 5: 'constexpr discord_ipc_cpp::json::JSON::JSON(const discord_ipc_cpp::json::JSON&)'
   69 | class JSON {
      |       ^~~~
/workspaces/obs-discord-rich-presence/src/discord_ipc_cpp/include/discord_ipc_cpp/json.hpp:69:7: note: candidate 6: 'constexpr discord_ipc_cpp::json::JSON::JSON(discord_ipc_cpp::json::JSON&&)'

This PR should fix the problem.

[TheMoonThatRises]

Thanks for the bug fix!