[fuchsia] Update ICU timezone data directory path to /config/tzdata/icu/44/le - #194241

On Fuchsia, the ICU timezone data capability tzdata-icu was factored out of config-data and mounted at /config/tzdata/icu (see meta/common.shard.cml and flutter-team-archive/engine#48907).

However, runner.cc still pointed to the legacy /config/data/tzdata/icu/44/le path under config-data. On modern Fuchsia builds where config-data no longer contains timezone files, flutter_runner fails to open the directory (Could not open: '/config/data/tzdata/icu/44/le') and falls back to bundled timezone data in icudtl.dat, ignoring the system timezone database.

This change updates kICUTZDataDir to /config/tzdata/icu/44/le to match common.shard.cml and the Dart VM's Fuchsia OS layer (runtime/vm/os_fuchsia.cc).

See:

• https://fuchsia.dev/fuchsia-src/development/internationalization/icu_data#timezone_configuration_data
• https://fuchsia.dev/fuchsia-src/concepts/process/namespaces

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities, or I am not using AI tools.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant in-code documentation (doc comments with ///).
• If this PR introduces a new feature or capability, I created and linked a website documentation issue or PR in flutter/website (or verified none is needed).
• I added new tests to check the change I am making, or this PR is test-exempt.
• I followed the breaking change policy and added Data Driven Fixes where supported.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

If this change needs to override an active code freeze, provide a comment explaining why. The code freeze workflow can be overridden by code reviewers. See pinned issues for any active code freezes with guidance.

Note: The Flutter team is currently trialing the use of Gemini Code Assist for GitHub. Comments from the gemini-code-assist bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.