Remove unused email templates

src/registrar/templates/emails/domain_manager_removed.txt

@@ -1,31 +0,0 @@
-{% autoescape off %}{# In a text file, we don't want to have HTML entities escaped #}
-Hi, {{ recipient.first_name }}.
-
-A domain manager was removed from {{ domain.name }}.
-
-REMOVED BY: {{ "populate" }}
-REMOVED ON: {{date}}
-MANAGER REMOVED: {{ "populate" }}
-
-
-----------------------------------------------------------------
-
-
-WHY DID YOU RECEIVE THIS EMAIL?
-
-You’re listed as a domain manager for {{ domain.name }}, so you’ll receive a notification whenever a domain manager is removed from that domain.
-If you have questions or concerns, reach out to the person who removed the domain manager or reply to this email.
-
-
-THANK YOU
-
-.Gov helps the public identify official, trusted information. Thank you for using a .gov domain.
-
-----------------------------------------------------------------
-
-The .gov team
-Contact us <https://get.gov/contact/> 
-Learn about .gov <https://get.gov>
-
-The .gov registry is a part of the Cybersecurity and Infrastructure Security Agency (CISA) <https://cisa.gov/>.
-{% endautoescape %}

src/registrar/templates/emails/domain_manager_removed_subject.txt

@@ -1 +0,0 @@
-A domain manager was removed from {{ domain.name }}