…ame 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: #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.