Explanation
This mule error is related to org.mule.tools.maven, as the yellow highlighted line in above screenshot is telling. There is an artifact called mule-maven-plugin which is not able to access the class org.apache.ignite.IgniteJdbcThinDriver in the ignite-core jar. So we need to tell the org.mule.tools.maven that look into ignite-core jar also during testing.
Solution
Open the pom.xml and adjust your plugin section as follows
<plugin>
<groupId>org.mule.tools.maven</groupId>
<artifactId>mule-maven-plugin</artifactId>
<version>${mule.maven.plugin.version}</version>
<extensions>true</extensions>
<configuration>
<sharedLibraries>
<sharedLibrary>
<groupId>org.apache.ignite</groupId>
<artifactId>ignite-core</artifactId>
</sharedLibrary>
</sharedLibraries>
<classifier>mule-application</classifier>
</configuration>
</plugin>
As you see I mentioned org.apache.ignite as shared library under plugin section for org.mule.tools.maven.
Well this will elevate the tooling exception error, which occur frequently in Anypoint Studio.