fix: prevent NaN timestamps from breaking event charts in Firefox

When date-fns-tz zonedTimeToUtc returns Invalid Date in Firefox,
the unary + operator produces NaN, which gets sent as "NaN" in
query parameters. Routes using z.coerce.number().int() validation
(events/series, event-data/properties) reject NaN as non-integer,
returning 400 errors and showing "Something went wrong".

This fix:
- Falls back to raw date timestamps when timezone conversion
  produces NaN in useDateParameters
- Filters out NaN values in getQueryString to prevent invalid
  parameters from reaching the server

Fixes #4121

src/components/hooks/useDateParameters.ts

@@ -7,9 +7,12 @@ export function useDateParameters() {
   } = useDateRange();
   const { timezone, localToUtc, canonicalizeTimezone } = useTimezone();
 
+  const startAtValue = +localToUtc(startDate);
+  const endAtValue = +localToUtc(endDate);
+
   return {
-    startAt: +localToUtc(startDate),
-    endAt: +localToUtc(endDate),
+    startAt: Number.isFinite(startAtValue) ? startAtValue : +startDate,
+    endAt: Number.isFinite(endAtValue) ? endAtValue : +endDate,
     startDate: localToUtc(startDate).toISOString(),
     endDate: localToUtc(endDate).toISOString(),
     unit,

src/lib/url.ts

@@ -2,7 +2,7 @@ export function getQueryString(params: object = {}): string {
   const searchParams = new URLSearchParams();
 
   Object.entries(params).forEach(([key, value]) => {
-    if (value !== undefined) {
+    if (value !== undefined && value !== null && !Number.isNaN(value)) {
       searchParams.append(key, value);
     }
   });