[BUG] Multiple datasource unable retrive datasource in the first time load dev tool

[Flyingliuhub]

Describe the bug

Multiple datasource unable retrieve datasource in the first time load of dev tool, the first time open dev tool throw the error with multiple datasource enabled.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'DataSource'
2. Click on 'Create Data source connection'
3. Fill out the required information and save
4. Click 'Dev Tools'
5. The 'Dev Tools' page throw error in the right bottom corner, "Unable to fetch existing data sources"

Expected behavior
It should successfully load 'Dev Tools' page.

OpenSearch Version
2.11

Dashboards Version
2.11

Plugins

Please list all plugins currently enabled.

Screenshots

Host/Environment (please complete the following information):

• OS: MacOS
• Browser and version firefox 115.5.0esr

Additional context

The 'Dev Tools' should render correctly when first time after create datasource

[Flyingliuhub]

@xinruiba will work this issue

[xinruiba]

Sure, will take a look @Flyingliuhub

[xinruiba]

With #5827, this issue should not shows up again.
Closing issue.