Refactor first name and last name extraction logic

Author: AnirudhBhat

example/src/test/java/org/wordpress/android/fluxc/model/customer/WCCustomerMapperTest.kt

@@ -451,6 +451,6 @@ class WCCustomerMapperTest {
         val result = mapper.mapToModel(site, customerDTO)
 
         // THEN
-        assertEquals("and a very long last name", result.lastName)
+        assertEquals("and  a   very  long last name", result.lastName)
     }
 }

plugins/woocommerce/src/main/kotlin/org/wordpress/android/fluxc/model/customer/WCCustomerMapper.kt

@@ -119,8 +119,8 @@ class WCCustomerMapper @Inject constructor() {
 
     // Please refer WCCustomerMapperTest file which serves as documentation of how this function behaves.
     private fun String?.firstNameFromName(): String =
-        this?.trim()?.replace("\\s+".toRegex(), " ")?.substringBefore(" ") ?: ""
+        this?.trim()?.substringBefore(' ')?.trim().orEmpty()
 
     private fun String?.lastNameFromName(): String =
-        this?.trim()?.replace("\\s+".toRegex(), " ")?.substringAfter(" ", "") ?: ""
+        this?.trim()?.substringAfter(' ', "")?.trim().orEmpty()
 }