Remove default_option to set release buildtype in Meson configuration

[WillAyd]

Describe the bug, including details regarding any error messages, version, and platform.

When setting up the Meson configuration, we set it to create release builds by default. However, with recent changes to Meson 1.8, and in theory when Apache Arrow may be used as a subproject, this default setting is either ignored or ambiguous. We should likely remove this.

See also the conversation in https://github.com/mesonbuild/wrapdb/issues/2208

Component(s)

C++