Standardise casing of integration manager

Replace instances of 'Integration Manager' with 'Integration manager', when at start of
sentence, or 'integration manager' when not.

Signed-off-by: Paulo Pinto <paulo.pinto@automattic.com>

src/components/views/dialogs/IntegrationsImpossibleDialog.js

@@ -46,7 +46,7 @@ export default class IntegrationsImpossibleDialog extends React.Component {
                 <div className='mx_IntegrationsImpossibleDialog_content'>
                     <p>
                         {_t(
-                            "Your %(brand)s doesn't allow you to use an Integration Manager to do this. " +
+                            "Your %(brand)s doesn't allow you to use an integration manager to do this. " +
                             "Please contact an admin.",
                             { brand },
                         )}