Fixed URLSearchParams constructor call

[codyebberson]

TypeScript definition for URLSearchParams constructor:

var URLSearchParams: new (init?: string | URLSearchParams | Record<string, string | readonly string[]> | Iterable<[string, string]> | readonly [string, string][] | undefined) => URLSearchParams

Before, we used the Record<string, string[]> variant, but apparently that is not widely available.

Now, we use the readonly [string, string][] variant, which appears to be ubiquitous.

https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams/URLSearchParams