fix: add support for spaces in search & enable searching by display name in templates (#19552)

## Summary

In this pull request we're updating search to support queries with
spaces in addition to the `field:value` pattern that is currently
supported.

Additionally templates search now defaults to `display_name` (since
`display_name` is optional the search will fallback to `name`) when
searching without the `field:value` pattern

Closes: https://github.com/coder/coder/issues/14384

### Downsides with searching on `name` and `display_name`

Because the `name` field cannot include spaces, we end up in a situation
where including a space in the query will result in no results since the
query searches on both `name` AND `display_name`. In the following
example, we can see the results of searching by both `name` and
`display_name` on these templates:

| Name | Display Name |
| ------ | ------------- |
| docker | Docker Template |
| faketemplate | A Fake Template |
| azure | Fake Azure Template |
| anotherfake | Another Fake Template |
| azurefake | Another Fake Fake Azure Template |



https://github.com/user-attachments/assets/b0e0793e-e77d-46bc-9a42-d7cf4f8bd910

### Proposal: Search on `display_name` by default and allow for `name`
using the `field:value` pattern

If we remove `name` from the default template search, we're now able to
search with spaces on template `display_names`. Since `display_names`
are what users see in the templates list they might expect the search to
work this way.

Below is an example of `name` being removed from the default template
search.


https://github.com/user-attachments/assets/9aba5911-4960-4384-befb-08ea1acaa3ab

With this approach users would still be able to search on template names
by specifying `exact_name:foo`.

### Testing

Added additional test cases to ensure spaces were handled as expected in
combination with `field:value` patterns.

coderd/database/queries/templates.sql

@@ -30,12 +30,30 @@ WHERE
 			LOWER(t.name) = LOWER(@exact_name)
 		ELSE true
 	END
+	-- Filter by exact display name
+	AND CASE
+		WHEN @exact_display_name :: text != '' THEN
+			LOWER(t.display_name) = LOWER(@exact_display_name)
+		ELSE true
+	END
 	-- Filter by name, matching on substring
 	AND CASE
 		WHEN @fuzzy_name :: text != '' THEN
 			lower(t.name) ILIKE '%' || lower(@fuzzy_name) || '%'
 		ELSE true
 	END
+	-- Filter by display_name, matching on substring (fallback to name if display_name is empty)
+	AND CASE
+		WHEN @fuzzy_display_name :: text != '' THEN
+			CASE
+				WHEN t.display_name IS NOT NULL AND t.display_name != '' THEN
+					lower(t.display_name) ILIKE '%' || lower(@fuzzy_display_name) || '%'
+				ELSE
+					-- Remove spaces if present since 't.name' cannot have any spaces
+					lower(t.name) ILIKE '%' || REPLACE(lower(@fuzzy_display_name), ' ', '') || '%'
+			END
+		ELSE true
+	END
 	-- Filter by ids
 	AND CASE
 		WHEN array_length(@ids :: uuid[], 1) > 0 THEN