Bug: refactor: reframe blocklist primary key for v2



## Description

Previously our Blocklist table had `id` as PKey. 
Which needs to be changed to a composite Primary key as `(merchant_id, fingerprint_id)`.
diff --git a/crates/diesel_models/src/schema.rs b/crates/diesel_models/src/schema.rs
index a5185dc6076..1242368404a 100644
--- a/crates/diesel_models/src/schema.rs
+++ b/crates/diesel_models/src/schema.rs
@@ -128,7 +128,7 @@ diesel::table! {
     use diesel::sql_types::*;
     use crate::enums::diesel_exports::*;
 
-    blocklist (id) {
+    blocklist (merchant_id, fingerprint_id) {
         id -> Int4,
         #[max_length = 64]
         merchant_id -> Varchar,
diff --git a/crates/diesel_models/src/schema_v2.rs b/crates/diesel_models/src/schema_v2.rs
index da8729cf835..e66e62467db 100644
--- a/crates/diesel_models/src/schema_v2.rs
+++ b/crates/diesel_models/src/schema_v2.rs
@@ -128,7 +128,7 @@ diesel::table! {
     use diesel::sql_types::*;
     use crate::enums::diesel_exports::*;
 
-    blocklist (id) {
+    blocklist (merchant_id, fingerprint_id) {
         id -> Int4,
         #[max_length = 64]
         merchant_id -> Varchar,
diff --git a/migrations/2024-07-17-174449_change_primary_key_for_blocklist_table/down.sql b/migrations/2024-07-17-174449_change_primary_key_for_blocklist_table/down.sql
new file mode 100644
index 00000000000..9600ce5addf
--- /dev/null
+++ b/migrations/2024-07-17-174449_change_primary_key_for_blocklist_table/down.sql
@@ -0,0 +1,5 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE blocklist DROP CONSTRAINT blocklist_pkey;
+
+ALTER TABLE blocklist
+ADD PRIMARY KEY (id);
diff --git a/migrations/2024-07-17-174449_change_primary_key_for_blocklist_table/up.sql b/migrations/2024-07-17-174449_change_primary_key_for_blocklist_table/up.sql
new file mode 100644
index 00000000000..c0df6d6345c
--- /dev/null
+++ b/migrations/2024-07-17-174449_change_primary_key_for_blocklist_table/up.sql
@@ -0,0 +1,12 @@
+-- Your SQL goes here
+-- The below query will lock the blocklist table
+-- Running this query is not necessary on higher environments
+-- as the application will work fine without these queries being run
+-- This query should be run after the new version of application is deployed
+ALTER TABLE blocklist DROP CONSTRAINT blocklist_pkey;
+
+-- Use the `merchant_id, fingerprint_id` columns as primary key
+-- These are already unique, not null columns
+-- So this query should not fail for not null or duplicate value reasons
+ALTER TABLE blocklist
+ADD PRIMARY KEY (merchant_id, fingerprint_id);

## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
Previously our Blocklist table had `id` as PKey. 
Which needs to be changed to a composite Primary key as `(merchant_id, fingerprint_id)`.

### Additional Changes

- [ ] This PR modifies the API contract
- [x] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!--
Provide links to the files with corresponding changes.

Following are the paths where you can find config files:
1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->


## Motivation and Context
<!--
Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

If you don't have an issue, we'd recommend starting with one first so the PR
can focus on the implementation (unless it is an obvious bug or documentation fix
that will have little conversation).
-->
Required for V2

## How did you test it?
<!--
Did you write an integration/unit/API test to verify the code changes?
Or did you test this change manually (provide relevant screenshots)?
-->
Tested it by running the blocklist Apis, which is performing fine as the id field was no where being used.

## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt --all`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible
