console_adapter: support console gem v1.30

[Watson1978]

Which issue(s) this PR fixes:
Fixes #

What this PR does / why we need it:
This patch will fix following error:

NoMethodError: undefined method `seek' for nil:NilClass
/home/runner/work/fluentd/fluentd/lib/fluent/log/console_adapter.rb:61:in `call'
/opt/hostedtoolcache/Ruby/3.2.7/x64/lib/ruby/gems/3.2.0/gems/console-1.30.0/lib/console/output/wrapper.rb:35:in `call'
/opt/hostedtoolcache/Ruby/3.2.7/x64/lib/ruby/gems/3.2.0/gems/console-1.30.0/lib/console/output/failure.rb:38:in `call'
/opt/hostedtoolcache/Ruby/3.2.7/x64/lib/ruby/gems/3.2.0/gems/console-1.30.0/lib/console/filter.rb:48:in `block (3 levels) in []'
/home/runner/work/fluentd/fluentd/test/log/test_console_adapter.rb:58:in `test_args'

Ref. https://github.com/fluent/fluentd/actions/runs/13714056838

The variable name was changed at
socketry/console@1529fef#diff-757206aeb67c0bd1c0d1813dfbff0a140a68920505520e8163b3a274fbab05ceR30

Since now Fluentd assumes Ruby 3.2 or later, this discards the related code to support Ruby before v3.1.

Docs Changes:
Not needed.

Release Note:
The same as the title.

[daipom]

Thanks! Good catch!