(core) Change default team logo

Summary:
Also fixes a bug that prevented drag and drop from working
in BillingLogoEditor, and tweaks the hover state of AppHeader
to only activate when the cursor is over the dropdown menu, and
not the logo.

Test Plan:
Manual.
1. Wide logo tests with url http://localhost:8080/o/docs?__themeOrg=fieldlink
2. Avatar on home screen for personal site
3. Avatar on doc screen for personal site
4. Avatar on doc screen with hidden left drawer on doc page
5. Same tests but with personal image
6. Same tests but with custom logo uploaded
7. All above tests but with dark theme
8. All above but on mobile.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D4378

app/common/ThemePrefs-ti.ts

@@ -452,8 +452,8 @@ export const ThemeColors = t.iface([], {
   "markdown-cell-light-border": "string",
   "markdown-cell-medium-border": "string",
   "app-header-bg": "string",
-  "app-header-hover-bg": "string",
   "app-header-border": "string",
+  "app-header-border-hover": "string",
 });
 
 const exportedTypeSuite: t.ITypeSuite = {

app/common/ThemePrefs.ts

@@ -592,8 +592,8 @@ export interface ThemeColors {
 
   /* App Header */
   'app-header-bg': string;
-  'app-header-hover-bg': string;
   'app-header-border': string;
+  'app-header-border-hover': string;
 }
 
 export const ThemePrefsChecker = createCheckers(ThemePrefsTI).ThemePrefs as CheckerT<ThemePrefs>;

app/common/themes/GristDark.ts

@@ -571,6 +571,6 @@ export const GristDark: ThemeColors = {
 
   /* App Header */
   'app-header-bg': '#32323F',
-  'app-header-border': '#FFFFFF00',
-  'app-header-hover-bg': 'rgba(111,111,125,0.6)',
+  'app-header-border': '#32323f',
+  'app-header-border-hover': '#78788c',
 };

app/common/themes/GristLight.ts

@@ -572,5 +572,5 @@ export const GristLight: ThemeColors = {
   /* App header */
   'app-header-bg': 'var(--grist-theme-page-panels-main-panel-bg)',
   'app-header-border': 'var(--grist-theme-menu-border)',
-  'app-header-hover-bg': 'var(--grist-theme-hover)',
+  'app-header-border-hover': '#B0B0B0',
 };