fix: Core image builds for arm64 under CI (#2149)

## Description:
Attempt to fix [this
error](https://app.circleci.com/pipelines/github/kurtosis-tech/kurtosis/11230/workflows/88eae5e6-f3fd-4895-9af0-2685895b59d3/jobs/162867)
possible linked to NixOS/nix#5258.

## Is this change user facing?
NO

core/server/Dockerfile

@@ -2,6 +2,10 @@ FROM alpine:3.17
 
 # We need protobut-dev to run protobuf compiler against startosis .proto files
 RUN apk update && apk add --no-cache bash protobuf-dev sudo shadow curl xz
+
+# Install Nix
+# We need to set filter-syscalls to false to allow Nix to work properly inside a container: https://github.com/NixOS/nix/issues/5258
+ENV NIX_CONFIG=$'filter-syscalls = false\nexperimental-features = nix-command flakes'
 RUN sh <(curl -L https://nixos.org/nix/install) --daemon --yes
 
 ARG TARGETARCH

core/server/Dockerfile.debug

@@ -2,6 +2,10 @@ FROM alpine:3.19
 
 # We need protobut-dev to run protobuf compiler against startosis .proto files
 RUN apk update && apk add --no-cache bash protobuf-dev sudo shadow curl xz
+
+# Install Nix
+# We need to set filter-syscalls to false to allow Nix to work properly inside a container: https://github.com/NixOS/nix/issues/5258
+ENV NIX_CONFIG=$'filter-syscalls = false\nexperimental-features = nix-command flakes'
 RUN sh <(curl -L https://nixos.org/nix/install) --daemon --yes
 
 # Make sure that you changed the port inside the APIC's code before changing it here