GH-40495: [GLib] Use G_DECLARE_DERIVABLE_TYPE()

[kou]

Rationale for this change

Using G_DECLARE_DERIVABLE_TYPE() or its family is the recommended way to declare a class (type).

What changes are included in this PR?

Replace raw #defines with G_DECLARE_DERIVABLE_TYPE().

Are these changes tested?

Yes.

Are there any user-facing changes?

No.

• GitHub Issue: [GLib] Use G_DECLARE_DERIVABLE_TYPE() #40495

[github-actions]

⚠️ GitHub issue #40495 has been automatically assigned in GitHub to PR creator.

[kou]

+1

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 7 benchmarking runs that have been run so far on merge-commit d7a3f6d.

There was 1 benchmark result with an error:

• Commit Run on ursa-i9-9960x at 2024-03-13 15:13:16Z
  • tpch (R) with engine=arrow, format=parquet, language=R, memory_map=False, query_id=TPCH-13, scale_factor=10

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 3 possible false positives for unstable benchmarks that are known to sometimes produce them.