Replace 'userxx' with 'orgxx' in all test files when the user type is org (#27052)

Currently 'userxx' and 'orgxx' are both used as username in test files
when the user type is org, which is confusing. This PR replaces all
'userxx' with 'orgxx' when the user type is org(`user.type==1`).
Some non-trivial changes
1. Rename `user3` dir to `org3` in `tests/git-repositories-meta` 
2. Change `end` in `issue reference` because 'org3' is one char shorter
than 'user3'

![ksnip_20230913-112819](https://github.com/go-gitea/gitea/assets/70063547/442988c5-4cf4-49b8-aa01-4dd6bf0ca954)
3. Change the search result number of `user/repo2` because
`user3/repo21` can't be searched now

![ksnip_20230913-112931](https://github.com/go-gitea/gitea/assets/70063547/d9ebeba4-479f-4110-9a85-825efbc981fd)
4. Change the first org name getting from API because the result is
ordered by alphabet asc and now `org 17` is before `org25`
![JW8U7NIO(J$H
_YCRB36H)T](https://github.com/go-gitea/gitea/assets/70063547/f55a685c-cf24-40e5-a87f-3a2327319548)
![)KFD411O4I8RB5ZOH7E0
Z3](https://github.com/go-gitea/gitea/assets/70063547/a0dc3299-249c-46f6-91cb-d15d4ee88dd5)

Other modifications are just find all and replace all.
Unit tests with SQLite are all passed.

---------

Co-authored-by: caicandong <1290147055@qq.com>

models/fixtures/repository.yml

@@ -64,7 +64,7 @@
 -
   id: 3
   owner_id: 3
-  owner_name: user3
+  owner_name: org3
   lower_name: repo3
   name: repo3
   default_branch: master
@@ -126,7 +126,7 @@
 -
   id: 5
   owner_id: 3
-  owner_name: user3
+  owner_name: org3
   lower_name: repo5
   name: repo5
   num_watches: 0
@@ -671,7 +671,7 @@
 -
   id: 23
   owner_id: 17
-  owner_name: user17
+  owner_name: org17
   lower_name: big_test_public_4
   name: big_test_public_4
   num_watches: 0
@@ -701,7 +701,7 @@
 -
   id: 24
   owner_id: 17
-  owner_name: user17
+  owner_name: org17
   lower_name: big_test_private_4
   name: big_test_private_4
   num_watches: 0
@@ -791,7 +791,7 @@
 -
   id: 27
   owner_id: 19
-  owner_name: user19
+  owner_name: org19
   lower_name: big_test_public_mirror_6
   name: big_test_public_mirror_6
   num_watches: 0
@@ -821,7 +821,7 @@
 -
   id: 28
   owner_id: 19
-  owner_name: user19
+  owner_name: org19
   lower_name: big_test_private_mirror_6
   name: big_test_private_mirror_6
   num_watches: 0
@@ -942,7 +942,7 @@
 -
   id: 32 # org public repo
   owner_id: 3
-  owner_name: user3
+  owner_name: org3
   lower_name: repo21
   name: repo21
   num_watches: 0