style(native): fix linting issues

Author: ACR1209

packages/native/src/lib/ElementAssertion.ts

@@ -2,7 +2,7 @@ import { Assertion, AssertionError } from "@assertive-ts/core";
 import { get } from "dot-prop-immutable";
 import { ReactTestInstance } from "react-test-renderer";
 
-import { instanceToString, isEmpty, getFlattenedStyle, styleToString  } from "./helpers/helpers";
+import { instanceToString, isEmpty, getFlattenedStyle, styleToString } from "./helpers/helpers";
 import { AssertiveStyle } from "./helpers/types";
 
 export class ElementAssertion extends Assertion<ReactTestInstance> {

packages/native/src/lib/helpers/helpers.ts

@@ -1,7 +1,7 @@
 import { StyleSheet } from "react-native";
 import { ReactTestInstance } from "react-test-renderer";
-import { AssertiveStyle, StyleObject } from "./types";
 
+import { AssertiveStyle, StyleObject } from "./types";
 
 /**
  * Checks if a value is empty.
@@ -35,13 +35,12 @@ export function instanceToString(instance: ReactTestInstance | null): string {
   return `<${instance.type.toString()} ... />`;
 }
 
-
 export function getFlattenedStyle(style: AssertiveStyle): StyleObject {
     const flattenedStyle = StyleSheet.flatten(style);
     return flattenedStyle ? (flattenedStyle as StyleObject) : {};
 }
 
 export function styleToString(flattenedStyle: StyleObject): string {
   const styleEntries = Object.entries(flattenedStyle);
-  return styleEntries.map(([key, value]) => `\t- ${key}: ${value};`).join("\n");
+  return styleEntries.map(([key, value]) => `\t- ${key}: ${String(value)};`).join("\n");
 }