fix: add retry logic to runner start script for libicu download (#3748)

## Background
---
There seems to be a race condition some where with the user-data script
and the EC2 starting up and locking RPM. This issue is seen elsewhere,
not necessarily with this repo's user-data, see the following:

[Amazon Linux 2023 - issue with installing packages with
cloud-init](https://repost.aws/questions/QU_tj7NQl6ReKoG53zzEqYOw/amazon-linux-2023-issue-with-installing-packages-with-cloud-init)

[dnf/yum both fails while being executed on instance bootstrap on Amazon
Linux
2023](https://repost.aws/questions/QUgNz4VGCFSC2TYekM-6GiDQ/dnf-yum-both-fails-while-being-executed-on-instance-bootstrap-on-amazon-linux-2023)

Also, #3741

## Changes Made
---
Added a loop to retry if the rpm lock file is found which sleeps for 5
seconds then retries again with a total of 5 iterations.

## Testing
---
Spun up an instance and ran the script directly (using sudo the second
time because this was not run via user-data)
<img width="339" alt="image"
src="https://github.com/philips-labs/terraform-aws-github-runner/assets/16331726/33679c00-b092-4900-80fd-838bb6c31409">

---------

Co-authored-by: Niek Palm <npalm@users.noreply.github.com>

modules/runners/templates/install-runner.sh

@@ -47,7 +47,20 @@ echo OS: $os_id
 
 # Install libicu on non-ubuntu
 if [[ ! "$os_id" =~ ^ubuntu.* ]]; then
-  dnf install -y libicu
+  max_attempts=5
+  attempt_count=0
+  success=false
+  while [ $success = false ] && [ $attempt_count -le $max_attempts ]; do
+    echo "Attempt $attempt_count/$max_attempts: Installing libicu"
+    dnf install -y libicu
+    if [ $? -eq 0 ]; then
+      success=true
+    else
+      echo "Failed to install libicu"
+      attempt_count=$(( attempt_count + 1 ))
+      sleep 5
+    fi
+  done
 fi
 
 # Install dependencies for ubuntu