Allow any Font Awesome style for the OAuth2 button icon (#7641)

docs/en_US/oauth2.rst

@@ -63,7 +63,7 @@ and secure.
     "OAUTH2_API_BASE_URL", "Oauth2 base URL endpoint to make requests simple, ex: *https://api.github.com/*"
     "OAUTH2_USERINFO_ENDPOINT", "User Endpoint, ex: *user* (for github, or *user/emails* if the user's email address is private) and *userinfo* (for google). **For OIDC providers**, this is optional if the ID token contains sufficient claims (email, preferred_username, or sub)."
     "OAUTH2_SCOPE", "Oauth scope, ex: 'openid email profile'. **For OIDC providers**, include 'openid' scope to receive an ID token."
-    "OAUTH2_ICON", "The Font-awesome icon to be placed on the oauth2 button,  ex: fa-github"
+    "OAUTH2_ICON", "The Font Awesome icon to be placed on the oauth2 button. A brand icon name (e.g. fa-github) uses the brands style by default; to use another style, include the style class explicitly (e.g. 'fas fa-key')."
     "OAUTH2_BUTTON_COLOR", "Oauth2 button color"
     "OAUTH2_USERNAME_CLAIM", "The claim which is used for the username. If the value is empty, **for OIDC providers** pgAdmin will use: 1) email, 2) preferred_username, or 3) sub (in that order). **For OAuth2 providers** without OIDC, email is required. Ex: *oid* (for AzureAD), *email* (for Github), *preferred_username* (for Keycloak)"
     "OAUTH2_AUTO_CREATE_USER", "Set the value to *True* if you want to automatically

docs/en_US/release_notes_9_16.rst

@@ -20,6 +20,8 @@ Bundled PostgreSQL Utilities
 New features
 ************
 
+  | `Issue #7641 <https://github.com/pgadmin-org/pgadmin4/issues/7641>`_ -  Allow the OAuth2 login button icon to use any Font Awesome style (e.g. ``fas fa-key``), not only brand icons.
+
 Housekeeping
 ************
 

web/pgadmin/static/js/SecurityPages/LoginPage.jsx

@@ -46,9 +46,16 @@ export default function LoginPage({userLanguage, langOptions, forgotPassUrl, csr
           }
           {authSources?.includes?.(authSourcesEnum.OAUTH2) &&
           oauth2Config.map((oauth)=>{
+            // Allow the configured icon to specify its own Font Awesome style
+            // (e.g. 'fas fa-key'). Default to the brands style ('fab') when
+            // only an icon name is given, for backward compatibility.
+            const iconStyles = ['fab', 'fas', 'far', 'fal', 'fat', 'fad',
+              'fa-brands', 'fa-solid', 'fa-regular', 'fa-light', 'fa-thin', 'fa-duotone'];
+            const hasStyle = oauth.OAUTH2_ICON?.split(/\s+/).some((c)=>iconStyles.includes(c));
+            const iconClassName = hasStyle ? oauth.OAUTH2_ICON : 'fab '+oauth.OAUTH2_ICON;
             return (
               <SecurityButton key={oauth.OAUTH2_NAME} name="oauth2_button" value={oauth.OAUTH2_NAME} style={{backgroundColor: oauth.OAUTH2_BUTTON_COLOR}}>
-                <Icon className={'fab '+oauth.OAUTH2_ICON} style={{ fontSize: '1.5em', marginRight: '8px' }} />{gettext('Login with %s', oauth.OAUTH2_DISPLAY_NAME)}
+                <Icon className={iconClassName} style={{ fontSize: '1.5em', marginRight: '8px' }} />{gettext('Login with %s', oauth.OAUTH2_DISPLAY_NAME)}
               </SecurityButton>
             );
           })