[ENH] Clean DB before applying (for now) (chroma-core#1896)

## Description of changes

*Summarize the changes made by this PR.*
 - New functionality
	 - Call `atlas schema clean` before applying migrations.

## Test plan
*How are these changes tested?*

- [ ] Tests pass locally with `pytest` for python, `yarn test` for js,
`cargo test` for rust

## Documentation Changes
*Are all docstrings for user-facing APIs updated if required? Do we need
to make documentation changes in the [docs
repository](https://github.com/chroma-core/docs)?*

k8s/distributed-chroma/templates/sysdb-migration.yaml

@@ -14,7 +14,7 @@ spec:
         - command:
             - "/bin/sh"
             - "-c"
-            - "atlas migrate apply --url postgres://{{ .Values.sysdbMigration.username }}:{{ .Values.sysdbMigration.password }}@{{ .Values.sysdbMigration.netloc }}:{{ .Values.sysdbMigration.port }}/{{ .Values.sysdbMigration.dbName }}?sslmode={{ .Values.sysdbMigration.sslmode }}"
+            - "atlas schema clean && atlas migrate apply --url postgres://{{ .Values.sysdbMigration.username }}:{{ .Values.sysdbMigration.password }}@{{ .Values.sysdbMigration.netloc }}:{{ .Values.sysdbMigration.port }}/{{ .Values.sysdbMigration.dbName }}?sslmode={{ .Values.sysdbMigration.sslmode }}"
           image: "{{ .Values.sysdbMigration.image.repository }}:{{ .Values.sysdbMigration.image.tag }}"
           imagePullPolicy: IfNotPresent
           name: migration