PFDA - G4SSM updates

[ihitch]

• generate .svg for step view (remove scheme view)
• Add "Add Draft" button to G4 and enable referencing drafts in the form
• Add bulk submission of draft substances
• Add Save Local Batch to G4 to download the G4 json + draft jsons referenced
• Change behavior of saving chemical drafts - generate uuid directly upon saving.

Please review our changes carefully; we had to resolve a ton of merge conflicts with the latest development_3.0 branch, so hopefully it didn't break anything on your end. We tested it on our instance, and it works as expected.

[iaromoskviak]

• In substance-drafts.component.ts (submit flow), the loading state is being turned off inside each individual request. So if you submit multiple drafts, the spinner can disappear after the first one finishes even though others are still running. This can make it look like everything completed when it hasn’t. I think this should wait until all submissions finish (e.g., forkJoin or a completion counter).

• Since this PR was opened before 676/677 were merged, I think you should rebase or merge latest development_3.0 into this branch and do one more test pass. Given how many core files this touches, there’s a real risk that conflict resolution may have unintentionally overridden newer behavior.

[ihitch]

@iaromoskviak Thanks for the feedback. I've updated the drafts submit flow to ensure the loading spinner stays active until all submissions are complete.

As for testing against the latest development_3.0 changes, we actually had QA test build 3.2.0 with this exact frontend branch (pfda_g4_pr). All of our regression tests passed and QA gave us the green light, so everything is working fine and no further testing should be needed.