[typescript-fetch] fix definition of fetchApi in configuration (#10164)

Created by: javier-garcia-meteologica

Fix definition of fetchApi in configuration to solve typescript compilation errors (#10164)

@wing328 @TiFu @taxpon @sebastianhaas @kenisteward @Vrolijkx @macjohnny @topce @akehir @petejohansonxo @amakhrov

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