fix(coderd): list templates returns non-deprecated templates by default (#17747)

## Description

Modifies the behaviour of the "list templates" API endpoints to return
non-deprecated templates by default. Users can still query for
deprecated templates by specifying the `deprecated=true` query
parameter.

**Note:** The deprecation feature is an enterprise-level feature

## Affected Endpoints
* /api/v2/organizations/{organization}/templates
* /api/v2/templates

Fixes #17565

coderd/apidoc/swagger.json

@@ -3628,6 +3628,7 @@
 						"CoderSessionToken": []
 					}
 				],
+				"description": "Returns a list of templates for the specified organization.\nBy default, only non-deprecated templates are returned.\nTo include deprecated templates, specify `deprecated:true` in the search query.",
 				"produces": ["application/json"],
 				"tags": ["Templates"],
 				"summary": "Get templates by organization",
@@ -4355,6 +4356,7 @@
 						"CoderSessionToken": []
 					}
 				],
+				"description": "Returns a list of templates.\nBy default, only non-deprecated templates are returned.\nTo include deprecated templates, specify `deprecated:true` in the search query.",
 				"produces": ["application/json"],
 				"tags": ["Templates"],
 				"summary": "Get all templates",