acceptance: use templates for bundle_default_profile scenarios (#5270)

## Summary

Follow-up to #5214 (per [pietern's review
comment](#5214 (comment))).

Replace the inline heredocs in
`acceptance/auth/bundle_default_profile/script` with three committed
templates:

- `databricks.yml.no-host.tmpl` — bundle with neither `workspace.host`
nor `workspace.profile`. Used for the "default_profile is honored" and
"`--profile` overrides" phases.
- `databricks.yml.with-host.tmpl` — pins `workspace.host:
$DATABRICKS_HOST`. `envsubst` fills in the test server URL before each
invocation.
- `databricks.yml.with-profile.tmpl` — pins `workspace.profile: other`.

Before each phase the script overwrites the active `databricks.yml` from
the relevant template. The per-scenario subdirectories
(`./bundle-with-host`, `./bundle-with-profile`) and the `cd` calls are
gone — the active bundle is always at the test root.

Stacked on #5266 (sethome-absolute fix). The base will auto-retarget to
`main` once #5266 merges.

`output.txt` is unchanged across the refactor: both engine variants
(`terraform` and `direct`) produce byte-identical output to the
pre-refactor run.

## Test plan

- [x] `go test ./acceptance -run TestAccept/auth/bundle_default_profile
-v` passes for both `DATABRICKS_BUNDLE_ENGINE=terraform` and `=direct`.
- [x] `./task fmt-q` and `./task lint-q` clean.

This pull request and its description were written by Isaac.

Author: janniklasrose

…th/bundle_default_profile/databricks.yml …ault_profile/databricks.yml.no-host.tmplacceptance/auth/bundle_default_profile/databricks.yml renamed to acceptance/auth/bundle_default_profile/databricks.yml.no-host.tmpl acceptance/auth/bundle_default_profile/databricks.yml renamed to acceptance/auth/bundle_default_profile/databricks.yml.no-host.tmpl

@@ -0,0 +1,5 @@
+bundle:
+  name: bundle-with-host
+
+workspace:
+  host: $DATABRICKS_HOST

acceptance/auth/bundle_default_profile/databricks.yml.with-host.tmpl

@@ -0,0 +1,5 @@
+bundle:
+  name: bundle-with-profile
+
+workspace:
+  profile: other

acceptance/auth/bundle_default_profile/databricks.yml.with-profile.tmpl

@@ -20,39 +20,25 @@ unset DATABRICKS_HOST
 unset DATABRICKS_TOKEN
 unset DATABRICKS_CONFIG_PROFILE
 
+cp databricks.yml.no-host.tmpl databricks.yml
 title "Bundle without workspace.host: default_profile is honored\n"
 trace $CLI bundle validate -o json | jq '{host: .workspace.host, profile: .workspace.profile}'
 
+cp databricks.yml.no-host.tmpl databricks.yml
 title "--profile overrides default_profile (negative case)\n"
 trace errcode $CLI bundle validate -p other -o json | jq '{host: .workspace.host, profile: .workspace.profile}'
 
 # Switch to a bundle that pins workspace.host. The default_profile guard in
 # configureProfile must NOT apply default_profile here, because that would
 # silently route the user to a profile pointing at a different host than the
 # bundle declares.
-mkdir -p ./bundle-with-host
-cat > ./bundle-with-host/databricks.yml <<EOF
-bundle:
-  name: bundle-with-host
-
-workspace:
-  host: $host_value
-EOF
-
+DATABRICKS_HOST="$host_value" envsubst < databricks.yml.with-host.tmpl > databricks.yml
 title "Bundle with workspace.host: default_profile is NOT applied\n"
-(cd ./bundle-with-host && trace errcode $CLI bundle validate -o json | jq '{host: .workspace.host, profile: .workspace.profile}')
+trace errcode $CLI bundle validate -o json | jq '{host: .workspace.host, profile: .workspace.profile}'
 
 # Switch to a bundle that pins workspace.profile but no host. The pinned
 # profile must win over default_profile — configureProfile's guard skips
 # default_profile when workspace.profile is already set.
-mkdir -p ./bundle-with-profile
-cat > ./bundle-with-profile/databricks.yml <<EOF
-bundle:
-  name: bundle-with-profile
-
-workspace:
-  profile: other
-EOF
-
+cp databricks.yml.with-profile.tmpl databricks.yml
 title "Bundle with workspace.profile: pinned profile wins over default_profile\n"
-(cd ./bundle-with-profile && trace errcode $CLI bundle validate -o json | jq '{host: .workspace.host, profile: .workspace.profile}')
+trace errcode $CLI bundle validate -o json | jq '{host: .workspace.host, profile: .workspace.profile}'

acceptance/auth/bundle_default_profile/script

@@ -1,8 +1,7 @@
 Ignore = [
     "home",
     ".databricks",
-    "bundle-with-host",
-    "bundle-with-profile",
+    "databricks.yml",
 ]
 
 # Negative case: -p other tries to reach a non-existing host. Redact the