Say which legacy protocols are off when only some are

inbuxa can now switch IMAP, POP3 and ManageSieve off one at a time,
server-wide and per organization, and the session lists what is still
allowed for the account (legacyAllowed). Where the webmail said
"legacy protocols are off", it now also covers the case where only
some are:

- Security & sessions, above app passwords: "Your organization has
  turned off POP3 for mail apps. Mail apps that use it can't connect
  to this account; others still can."
- The Administration dashboard: "Some legacy mail protocols are off for
  your organization: POP3."
- An organization's sheet in Administration: its switch stays the
  all-or-nothing one; when only some are off it names them and points
  to the console, where they're switched one at a time, and "Turn
  legacy protocols back on" turns them all back on.

With every protocol off, the existing wording shows, as before. From a
server that doesn't send legacyAllowed nothing new appears.

3 new strings in all nine catalogs, unreviewed.

Tested: unit tests for reading the session and a tenant's switches;
the existing tests updated for the new field; typecheck; the whole
suite (1475 tests); and in headless Chrome against a local server with
POP3 off, where Security & sessions showed the new note.

web/src/views/admin/__tests__/tenant-legacy-protocols.test.tsx

@@ -62,7 +62,7 @@ describe("a tenant's legacy mail protocols switch", () => {
   });
 
   it("shows who would notice and what it means, then asks for the exact phrase", async () => {
-    api.state = { off: false, recent: [{ accountId: "a", name: "[email protected]", protocol: "imap", lastUsedAt: Date.now() - 2 * 86400_000 }] };
+    api.state = { off: false, partlyOff: [], recent: [{ accountId: "a", name: "[email protected]", protocol: "imap", lastUsedAt: Date.now() - 2 * 86400_000 }] };
     signIn(["sysDomainGet", "sysDomainUpdate"]);
     await render();
     await act(async () => button(host, "Turn off legacy protocols…")!.click());
@@ -84,7 +84,7 @@ describe("a tenant's legacy mail protocols switch", () => {
   });
 
   it("turns it back on with one click", async () => {
-    api.state = { off: true, recent: [] };
+    api.state = { off: true, partlyOff: [], recent: [] };
     signIn(["sysDomainGet", "sysDomainUpdate"]);
     await render();
     await act(async () => button(host, "Turn legacy protocols back on")!.click());
@@ -92,7 +92,7 @@ describe("a tenant's legacy mail protocols switch", () => {
   });
 
   it("shows the state but no switch to someone who can't change domains", async () => {
-    api.state = { off: true, recent: null };
+    api.state = { off: true, partlyOff: [], recent: null };
     signIn(["sysDomainGet"]);
     await render();
     expect(host.textContent).toContain("Off for Acme Corp");