Properly address null possibility in buildAndSendDownloadPdfRequest()

[monocle]

recordexpungPDX/src/frontend/src/redux/search/actions.ts

Lines 78 to 87 in 482877a

	function buildAndSendDownloadPdfRequest(dispatch: any): any {
	return apiService(dispatch, {
	url: "/api/pdf",
	data: buildSearchRequest(),
	method: "post",
	withCredentials: true,
	responseType: "blob",
	})
	.then((response: AxiosResponse) => {
	const filename = (response.headers["content-disposition"] ?? "")

For line 87, a null guard was added to fix a TS warning about response.headers["content-disposition"] being potentially null
482877a.

Need to determine what the proper handling is for this.