fix(storybook-builder): start relative path with ./

Author: bashmish

.changeset/weak-parrots-push.md

@@ -0,0 +1,5 @@
+---
+'@web/storybook-builder': patch
+---
+
+fix relative path by starting with ./

package-lock.json

@@ -58,7 +58,7 @@ export function esbuildPluginCommonjsNamedExports(modules: string[]): Plugin {
 
         return {
           resolveDir,
-          contents: `export { ${finalExports.join(',')} } from '${slash(
+          contents: `export { ${finalExports.join(',')} } from './${slash(
             relative(resolveDir, resolvedPath),
           )}';`,
         };