Incorrect link text - Step 26

The link text for next and previous are switched. Step 27 is about QUnit testing while step 25 is about remote OData services.

ui5-typescript-walkthrough/steps/26/README.md

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           **Next:** [Step 27: Remote OData Service](../27/README.md "Now that we have a test folder in the app, we can start to increase our test coverage.")

ui5-typescript-walkthrough/steps/26/README.md

Line 276 in 8344270

    
           **Previous:** [Step 25: Unit Test with QUnit](../25/README.md "So far we have worked with local JSON data, but now we will access a real OData service to visualize remote data.")