[Arrow] Consider faster way to check if a `Field` has an extension type

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

As @mbrobbel pointed out in https://github.com/apache/arrow-rs/pull/8408/files#r2378240955:

There are currently two APIs for seeing if a Field has an extension type:

• Field::extension_type that panics if the field does not have the extension type
• Field::try_extension_type that returns an ArrowError if the field does not have the extension type

There is no good API to quickly tell if a Field has an extension type. The current way is like

if field.try_extension_type<TheExtensionType>().is_ok() {
 // field has extension type
}

Works, but it requires creating an ArrowError if the field is not the requested type, which is slow as it allocates a String

in #8408 I came up with this to avoid the problem, but it is not obvious and somewhat redundant:

    // Check the name (= quick and cheap) and only try_extension_type if the name matches
    // to avoid unnecessary String allocations in ArrowError
    if field.extension_type_name()? != VariantType::NAME {
        return None;
    }
    match field.try_extension_type::<VariantType>() {
        Ok(VariantType) => Some(LogicalType::Variant),
        // Given check above, this should not error, but if it does ignore
        Err(_e) => None,
    }

Describe the solution you'd like
A clearer way to test for extension types.

Maybe the documentation I added in this PR are enough

• Add examples of using Field::try_extension_type #8475

Describe alternatives you've considered

Additional context