Handle exception separately for each span

[huaiyan]

Description

1. Handle exception separately for each span, we don't want failure of one span make the whole batch spans fail
2. Change default value of latency to None. Current value is 0.0, which is misleading for UX rendering.

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• The pull request does not introduce [breaking changes].
• CHANGELOG is updated for new features, bug fixes or other significant changes.
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Testing Guidelines

• Pull request includes test coverage for the included changes.

[github-actions]

promptflow SDK CLI Azure E2E Test Result dev/robbenwang_cloud_span_exception

  4 files    4 suites   5m 30s ⏱️
237 tests 203 ✅  34 💤 0 ❌
948 runs  812 ✅ 136 💤 0 ❌

Results for commit faa4b54.

♻️ This comment has been updated with latest results.

[github-actions]

SDK CLI Global Config Test Result dev/robbenwang_cloud_span_exception

4 tests   4 ✅  1m 19s ⏱️
1 suites  0 💤
1 files    0 ❌

Results for commit faa4b54.

♻️ This comment has been updated with latest results.

[github-actions]

Executor Unit Test Result dev/robbenwang_cloud_span_exception

792 tests   792 ✅  3m 42s ⏱️
  1 suites    0 💤
  1 files      0 ❌

Results for commit faa4b54.

♻️ This comment has been updated with latest results.

[github-actions]

Executor E2E Test Result dev/robbenwang_cloud_span_exception

240 tests   235 ✅  5m 9s ⏱️
  1 suites    5 💤
  1 files      0 ❌

Results for commit faa4b54.

♻️ This comment has been updated with latest results.

[github-actions]

SDK CLI Test Result dev/robbenwang_cloud_span_exception

    4 files      4 suites   1h 0m 35s ⏱️
  661 tests   648 ✅ 13 💤 0 ❌
2 644 runs  2 592 ✅ 52 💤 0 ❌

Results for commit faa4b54.

♻️ This comment has been updated with latest results.