Harden Telegram poll gating and schema consistency (#36547)

Merged via squash.

Prepared head SHA: f77824419e
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

src/polls.ts

@@ -26,6 +26,13 @@ type NormalizePollOptions = {
   maxOptions?: number;
 };
 
+export function resolvePollMaxSelections(
+  optionCount: number,
+  allowMultiselect: boolean | undefined,
+): number {
+  return allowMultiselect ? Math.max(2, optionCount) : 1;
+}
+
 export function normalizePollInput(
   input: PollInput,
   options: NormalizePollOptions = {},