[BUG] At first time, Import saved objects with check existing objects and automatically override, when there is no conflict and create new objects, still display {number} objects overwritten

[yujin-emma]

Describe the bug

Tried to import saved objects from local file, chose an empty data source, choose Check existing objects and automatically override, since there is no conflict, objects are imported as new objects, but still display overwritten, which is not correct
To Reproduce
Steps to reproduce the behavior:

1. Enable data source feature
2. Go to dashboards managements -> saved objects
3. import
4. choose a local file to upload
5. At Data source picker, choose an empty data source
6. choose check existing object and automatically override conflict
7. can see {number} objects override, but the total number of objects increase by {number}

Expected behavior
{number} objects new
OpenSearch Version
2.12
Dashboards Version
2.12
Plugins

Screenshots

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Host/Environment (please complete the following information):

• OS: [e.g. iOS]
• Browser and version [e.g. 22]

Additional context

Add any other context about the problem here.

[AMoo-Miki]

@yujin-emma noted that this is fixed with #5871