Add envelope settings step to wizard

Introduced a new step (step 2) in the `CreateEnvelopeWizardPopup` for configuring envelope settings, including security, reminders, and expiration options.

- Added fields for certification type, final email options, 2FA, access codes, and reminder settings.
- Updated step titles, descriptions, and total steps from 4 to 5.
- Implemented validation logic for the new settings step.
- Added methods to handle changes in settings fields and apply defaults.
- Updated `CreateEnvelopeWizardResult` and `CreateEnvelopeBootstrapPayload` to include new fields.
- Modified `SenderEditorPage` and `SenderPage` to handle new settings.
- Styled the new step with updated CSS for grids, groups, and toggles.
- Refactored state reset logic to initialize new fields.

EnvelopeGenerator.Server/EnvelopeGenerator.Server/wwwroot/css/sender-page.css

@@ -1242,6 +1242,40 @@
     grid-column: 1 / -1;
 }
 
+.sender-create-wizard__settings-grid {
+    display: grid;
+    gap: 0.8rem;
+}
+
+.sender-create-wizard__settings-group {
+    border: 1px solid rgba(148, 163, 184, 0.34);
+    border-radius: 10px;
+    background: rgba(248, 250, 252, 0.86);
+    padding: 0.8rem;
+}
+
+.sender-create-wizard__settings-title {
+    font-size: 0.8rem;
+    font-weight: 800;
+    color: #334155;
+    margin-bottom: 0.6rem;
+}
+
+.sender-create-wizard__settings-toggles {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.55rem 1.1rem;
+}
+
+.sender-create-wizard__settings-toggle {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.4rem;
+    font-size: 0.82rem;
+    font-weight: 600;
+    color: #334155;
+}
+
 .sender-create-wizard__label {
     font-size: 0.82rem;
     font-weight: 700;