[R][CI] Rhub job fails test missing EST timezone due to Ubuntu GH runner upgrade #55113

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

Rhub job on the R Extra CI is failing due to missing timezone:

── Error ('test-dplyr-funcs-type.R:998:3'): format date/time ───────────────────
Error in `compute.arrow_dplyr_query(x)`: Invalid: Cannot locate or parse timezone 'EST': EST not found in timezone database
Backtrace:

This is related to GitHub updating runners for ubuntu from 24.04 to 26.04 and missing tzdata-legacy. I'll push a fix.

Component(s)

Continuous Integration, R