Fix some ansible-lint-reported warnings

This mostly fixes `key-order` warnings around
`block` statements.

roles/matrix-postgres/tasks/import_generic_sqlite_db.yml

@@ -25,7 +25,8 @@
 # We either expect `postgres_db_connection_string` specifying a full Postgres database connection string,
 # or `postgres_connection_string_variable_name`, specifying a name of a variable, which contains a valid connection string.
 
-- block:
+- when: 'postgres_connection_string_variable_name is defined'
+  block:
     - name: Fail if postgres_connection_string_variable_name points to an undefined variable
       ansible.builtin.fail: msg="postgres_connection_string_variable_name is defined, but there is no variable with the name `{{ postgres_connection_string_variable_name }}`"
       when: "postgres_connection_string_variable_name not in vars"
@@ -33,7 +34,6 @@
     - name: Get Postgres connection string from variable
       ansible.builtin.set_fact:
         postgres_db_connection_string: "{{ lookup('vars', postgres_connection_string_variable_name) }}"
-  when: 'postgres_connection_string_variable_name is defined'
 
 - name: Fail if playbook called incorrectly
   ansible.builtin.fail:

roles/matrix-postgres/tasks/migrate_db_to_postgres.yml

@@ -31,7 +31,8 @@
     msg: "File cannot be found on the server at {{ matrix_postgres_db_migration_request.src }}"
   when: "not matrix_postgres_db_migration_request_src_stat_result.stat.exists"
 
-- block:
+- when: "matrix_postgres_pgloader_container_image_self_build | bool"
+  block:
     - name: Ensure pgloader repository is present on self-build
       ansible.builtin.git:
         repo: "{{ matrix_postgres_pgloader_container_image_self_build_repo }}"
@@ -69,7 +70,6 @@
           dockerfile: Dockerfile
           path: "{{ matrix_postgres_pgloader_container_image_self_build_src_path }}"
           pull: true
-  when: "matrix_postgres_pgloader_container_image_self_build | bool"
 
 - name: Ensure pgloader Docker image is pulled
   docker_image:
@@ -134,7 +134,8 @@
   register: matrix_postgres_migrate_db_to_postgres_import_result
   changed_when: matrix_postgres_migrate_db_to_postgres_import_result.rc == 0
 
-- block:
+- when: "matrix_postgres_db_migration_request.additional_psql_statements_list | default([]) | length > 0"
+  block:
     - ansible.builtin.import_role:
         name: matrix-postgres
         tasks_from: detect_existing_postgres_version
@@ -157,8 +158,6 @@
       register: matrix_postgres_migrate_db_to_postgres_additional_queries_result
       changed_when: matrix_postgres_migrate_db_to_postgres_additional_queries_result.rc == 0
 
-  when: "matrix_postgres_db_migration_request.additional_psql_statements_list | default([]) | length > 0"
-
 - name: Archive {{ matrix_postgres_db_migration_request.engine_old }} database ({{ matrix_postgres_db_migration_request.src }} -> {{ matrix_postgres_db_migration_request.src }}.backup)
   ansible.builtin.command:
     cmd: "mv {{ matrix_postgres_db_migration_request.src }} {{ matrix_postgres_db_migration_request.src }}.backup"

roles/matrix-postgres/tasks/migrate_postgres_data_directory.yml

@@ -52,14 +52,14 @@
     group: "{{ matrix_user_groupname }}"
   when: "result_pg_old_data_dir_stat.stat.exists"
 
-- block:
+- when: "result_pg_old_data_dir_stat.stat.exists"
+  block:
     - name: Relocate Postgres data files from old directory to new
       ansible.builtin.command:
         cmd: "mv {{ item.path }} {{ matrix_postgres_data_path }}/{{ item.path | basename }}"
       with_items: "{{ result_pg_old_data_dir_find.files }}"
       register: matrix_postgres_migrate_postgres_data_directory_move_result
       changed_when: matrix_postgres_migrate_postgres_data_directory_move_result.rc == 0
-  when: "result_pg_old_data_dir_stat.stat.exists"
 
 # Intentionally not starting matrix-postgres here.
 # It likely needs to be updated to point to the new directory.