[Sample]update sample env var to filter out sample data in telemetry

[D-W-]

Description

Please add an informative description that covers that changes made by the pull request and link all relevant issues.

All Promptflow Contribution checklist:

• The pull request does not introduce [breaking changes].
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.
• Create an issue and link to the pull request to get dedicated review from promptflow team. Learn more: suggested workflow.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[github-actions]

Executor Unit Test Result wanhan/update_ci

377 tests   376 ✔️  49s ⏱️
    1 suites      1 💤
    1 files        0 ❌

Results for commit 1d97b59.

[github-actions]

promptflow SDK CLI Azure E2E Test Result wanhan/update_ci

    2 files    2 suites   1m 1s ⏱️
  58 tests 36 ✔️ 22 💤 0 ❌
116 runs  72 ✔️ 44 💤 0 ❌

Results for commit 1d97b59.

[github-actions]

SDK CLI Global Config Test Result wanhan/update_ci

2 tests   2 ✔️  53s ⏱️
1 suites  0 💤
1 files    0 ❌

Results for commit 1d97b59.

[github-actions]

Executor E2E Test Result wanhan/update_ci

121 tests   119 ✔️  3m 17s ⏱️
    1 suites      2 💤
    1 files        0 ❌

Results for commit 1d97b59.

[github-actions]

SDK PFS E2E Test Result wanhan/update_ci

8 tests   8 ✔️  28s ⏱️
1 suites  0 💤
1 files    0 ❌

Results for commit 1d97b59.

[github-actions]

SDK CLI Test Result wanhan/update_ci

314 tests   301 ✔️  14m 26s ⏱️
    1 suites    13 💤
    1 files        0 ❌

Results for commit 1d97b59.