fix: Remove circular dependency

When bundling our SDK we were warned about circular dependency errors, because:

`src/utils/type-utils` depends on `src/utils/string-utils`
`src/utils/string-utils` depends on `src/utils`
`src/utils` depends on `src/string-utils`

We can remove the dependency by making `string-utils` self-contained copying the function it was importing from the index.

Turns out that function isn't being used anywhere else anyway.

src/utils/index.ts

@@ -107,15 +107,6 @@ export function entries<T = any>(obj: Record<string, T>): [string, T][] {
     return resArray
 }
 
-export const isValidRegex = function (str: string): boolean {
-    try {
-        new RegExp(str)
-    } catch {
-        return false
-    }
-    return true
-}
-
 export const trySafe = function <T>(fn: () => T): T | undefined {
     try {
         return fn()

src/utils/string-utils.ts

@@ -1,4 +1,11 @@
-import { isValidRegex } from '.'
+export const isValidRegex = function (str: string): boolean {
+    try {
+        new RegExp(str)
+    } catch {
+        return false
+    }
+    return true
+}
 
 export function includes<T = any>(str: T[] | string, needle: T): boolean {
     return (str as any).indexOf(needle) !== -1
@@ -19,6 +26,7 @@ export function isDistinctIdStringLike(value: string): boolean {
 
 export const isMatchingRegex = function (value: string, pattern: string): boolean {
     if (!isValidRegex(pattern)) return false
+
     try {
         return new RegExp(pattern).test(value)
     } catch {