Update check-online-doc-build.yml

[NeoZhangJianyu]

Description

Fix the build error issue, due to default ubuntu is upgraded to 24 by github in CI.
Use ubuntu-22.04 in CI to replace ubuntu-latest.

The build online python script use package 're'. The code doesn't work well on python 3.12 which is involved by ubuntu 24.

Fix ubuntu version is the solution of minimum risk/code/cost.

To fix this issue in root cause, there are alternatives:

1. update the code about 're' package to adapt to python 3.12 and 3.10 in same time.
2. remove the function to convert some warnings of sphinx to error in the build script.

The solution will depend on the next maintainer.

Issues

List the issue or RFC link this PR is working on. If there is no such link, please mark it as n/a.

Type of change

List the type of change like below. Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would break existing design and interface)

Dependencies

List the newly introduced 3rd party dependency if exists.

Tests

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