[ABW]: couple negative tests for get_follow_list

hivemind/tavern/bridge_api_negative/get_follow_list/bad_observer.pat.json

+{
+  "code": -32602,
+  "data": "Account nonexisting does not exist",
+  "message": "Invalid parameters"
+}

hivemind/tavern/bridge_api_negative/get_follow_list/bad_observer.tavern.yaml

+---
+  test_name: Hivemind bridge_api.get_follow_list invalid type patterns test
+
+  marks:
+    - patterntest # not present in old HM
+    - negative
+
+  includes:
+    - !include ../../common.yaml
+
+  stages:
+    - name: bridge_api.get_follow_list
+      request:
+        url: "{service.proto:s}://{service.server:s}:{service.port}/"
+        method: POST
+        headers:
+          content-type: application/json
+        json:
+          jsonrpc: "2.0"
+          id: 1
+          method: "bridge.get_follow_list"
+          params: {"follow_type":"follow_muted","observer":"nonexisting"}
+      response:
+        status_code: 200
+        verify_response_with:
+          function: validate_response:compare_response_with_pattern
+          extra_kwargs:
+            method: "bad_observer"
+            directory: "bridge_api_negative/get_follow_list"
+            error_response: true

hivemind/tavern/bridge_api_negative/get_follow_list/invalid_follow_type.pat.json

+{
+  "code": -32602,
+  "data": "Unsupported follow_type, valid values: blacklisted, follow_blacklist, muted, follow_muted",
+  "message": "Invalid parameters"
+}

hivemind/tavern/bridge_api_negative/get_follow_list/invalid_follow_type.tavern.yaml

+---
+  test_name: Hivemind bridge_api.get_follow_list invalid type patterns test
+
+  marks:
+    - patterntest # not present in old HM
+    - negative
+
+  includes:
+    - !include ../../common.yaml
+
+  stages:
+    - name: bridge_api.get_follow_list
+      request:
+        url: "{service.proto:s}://{service.server:s}:{service.port}/"
+        method: POST
+        headers:
+          content-type: application/json
+        json:
+          jsonrpc: "2.0"
+          id: 1
+          method: "bridge.get_follow_list"
+          params: {"follow_type":"invalid_type","observer":"alice"}
+      response:
+        status_code: 200
+        verify_response_with:
+          function: validate_response:compare_response_with_pattern
+          extra_kwargs:
+            method: "invalid_follow_type"
+            directory: "bridge_api_negative/get_follow_list"
+            error_response: true

hivemind/tavern/bridge_api_negative/get_follow_list/invalid_observer.pat.json

+{
+  "code": -32602,
+  "data": "invalid account name length: `nonexisting_account`",
+  "message": "Invalid parameters"
+}

hivemind/tavern/bridge_api_negative/get_follow_list/invalid_observer.tavern.yaml

+---
+  test_name: Hivemind bridge_api.get_follow_list invalid type patterns test
+
+  marks:
+    - patterntest # not present in old HM
+    - negative
+
+  includes:
+    - !include ../../common.yaml
+
+  stages:
+    - name: bridge_api.get_follow_list
+      request:
+        url: "{service.proto:s}://{service.server:s}:{service.port}/"
+        method: POST
+        headers:
+          content-type: application/json
+        json:
+          jsonrpc: "2.0"
+          id: 1
+          method: "bridge.get_follow_list"
+          params: {"follow_type":"follow_muted","observer":"nonexisting_account"}
+      response:
+        status_code: 200
+        verify_response_with:
+          function: validate_response:compare_response_with_pattern
+          extra_kwargs:
+            method: "invalid_observer"
+            directory: "bridge_api_negative/get_follow_list"
+            error_response: true