Large files in the keycloak chart cause Helm Secret size to exceed 1MiB

When attempting to import a 100 KiB realm file using a secret added to the Keycloak Helm chart, we encountered the following error:

Helm upgrade failed for release keycloak/keycloak with chart keycloak@2.5.1-bb.0: 
create: failed to create: Secret "sh.helm.release.v1.keycloak.v3" is invalid: 
data: Too long: must have at most 1048576 bytes

When examining the state of the prior Helmrelease version, the existing data was already very close to the Secret size limit:

$ k get secret -n bigbang sh.helm.release.v1.keycloak.v2 -oyaml | yq '.data.release' | base64 -d > sh.helm.release.v1.keycloak.v2.yaml
$ ls -l sh.helm.release.v1.keycloak.v2.yaml
-rw-------. 1 root root 997160 Nov  1 14:15 sh.helm.release.keycloak.yaml

Attempting to inspect the contents of the Secret reveals that it needs to be base64-decoded again and then gunzipped, resulting in the following:

$ base64 -d sh.helm.release.v1.keycloak.v2.yaml | gunzip > sh.helm.release.v1.keycloak.v2-unzipped.yaml
$ ls -l
-rw-------. 1 root root 1822118 Nov  1 14:37 sh.helm.release.v1.keycloak.v2-unzipped.yaml
-rw-------. 1 root root  997160 Nov  1 14:22 sh.helm.release.v1.keycloak.v2.yaml

The resulting data is in JSON format, with the following top-level keys and sizes:

$ yq 'keys()' sh.helm.release.v1.keycloak.v2-unzipped.yaml
- "name"
- "info"
- "chart"
- "config"
- "manifest"
- "version"
- "namespace"
$ yq '.name' sh.helm.release.v1.keycloak.v2-unzipped.yaml | wc -c
9
$ yq '.info' sh.helm.release.v1.keycloak.v2-unzipped.yaml | wc -c
937
$ yq '.chart' sh.helm.release.v1.keycloak.v2-unzipped.yaml | wc -c
1554589
$ yq '.config' sh.helm.release.v1.keycloak.v2-unzipped.yaml | wc -c
4307
$ yq '.manifest' sh.helm.release.v1.keycloak.v2-unzipped.yaml | wc -c
262641
$ yq '.version' sh.helm.release.v1.keycloak.v2-unzipped.yaml | wc -c
2
$ yq '.namespace' sh.helm.release.v1.keycloak.v2-unzipped.yaml | wc -c
9

As shown, the full contents of the Helm chart are stored in the Secret (so that Helm can calculate the differences between different Helm revisions), bloating the size of the Secret significantly.