[scripts] Fix terraform lint

Summary:
When reviewing D9877 I realized that terraform format lint doesn't work in pre-commit hook. Fixed this.
Also changed it to auto-format instead of failing.

Test Plan:
Made some formatting errors in terraform files, git staged them, and ran `yarn lint-staged`. It fixed them.

Output of `terraform_pre_commit.sh` (the `modules/shared/dynamodb.tf` was the file that was reformatted):
```
ᐅ ./scripts/terraform_pre_commit.sh
Formatting terraform...
modules/shared/dynamodb.tf
Validating 'dev' terraform configuration...
Success! The configuration is valid.

Validating 'remote' terraform configuration...
Success! The configuration is valid.
```

Reviewers: varun, wyilio

Reviewed By: varun

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D9958

scripts/terraform_pre_commit.sh

@@ -2,9 +2,15 @@
 
 set -e
 
-cd services/terraform
-echo "formatting services/terraform..."
-terraform fmt -check
-echo "validating services/terraform..."
-terraform validate
-echo "done formatting and validating"
+cd services/terraform/
+echo "Formatting terraform..."
+terraform fmt -recursive
+
+for cfg in dev remote; do
+  pushd "$cfg" >/dev/null
+  echo "Validating '$cfg' terraform configuration..."
+  terraform validate
+  popd >/dev/null
+done
+
+echo "Done formatting and validating terraform"