chore(igniter): use latest igniter and drop jason when it's not needed

[solnic]

⚠️ this builds on elixir-version-lockfiles - see #1114 first

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Bumps igniter to the latest version and makes it skip adding jason when we don't need it under newer Elixir versions with built-in JSON.

Dep-hell notes:

• Elixir 1.13 requires older dependencies that still compile on it (hpax must be pinned to 1.0.3 and for sure more are coming soon) - hence elixir-version-lockfiles branch that this one needs added dedicated lock file for Elixir 1.13.
• Elixir 1.14–1.17 needs pre-ExAST Igniter, because ExAST adds a global Jason encoder that changes Sentry behavior (a test failed due to differences in default JSON serialization of MapSet) - same, needed its own lock file.
• Elixir 1.18+ can use the latest Igniter safely because it uses native JSON - which we fully embrace too in the SDK 🎉 (and that's our silver lining of this short dependency story 😆)

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