ci: fix expired MySQL APT GPG key (B7B3B788A8D3785C)

keyserver.ubuntu.com still returns the expired copy of
BCA43417C3B485DD128EC6D4B7B3B788A8D3785C, causing every job that
installs from repo.mysql.com jammy to fail:

  W: GPG error: http://repo.mysql.com/apt/ubuntu jammy InRelease:
     EXPKEYSIG B7B3B788A8D3785C MySQL Release Engineering

MySQL re-signed the key with the same fingerprint (valid through
2027-10-23) and publishes it as RPM-GPG-KEY-mysql-2025. Fetch it
directly instead of from Ubuntu's keyserver.

Hits: ci-taptests, ci-taptests-asan, ci-taptests-groups,
ci-taptests-old, ci-taptests-ssl.

.github/workflows/ci-taptests-asan.yml

@@ -117,7 +117,8 @@ jobs:
         sudo dpkg -i orchestrator-client_3.2.6_amd64.deb
         
         sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 467B942D3A79BD29
-        sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A8D3785C
+        # Ubuntu keyserver serves the expired B7B3B788A8D3785C; fetch renewed key from MySQL.
+        wget -qO - https://repo.mysql.com/RPM-GPG-KEY-mysql-2025 | sudo apt-key add -
         wget https://repo.mysql.com/mysql-apt-config_0.8.29-1_all.deb
         sudo dpkg -i mysql-apt-config_0.8.29-1_all.deb
         sudo apt-get update -y

.github/workflows/ci-taptests-groups.yml

@@ -132,7 +132,8 @@ jobs:
         sudo dpkg -i orchestrator-client_3.2.6_amd64.deb
         
         sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 467B942D3A79BD29
-        sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A8D3785C
+        # Ubuntu keyserver serves the expired B7B3B788A8D3785C; fetch renewed key from MySQL.
+        wget -qO - https://repo.mysql.com/RPM-GPG-KEY-mysql-2025 | sudo apt-key add -
         wget https://repo.mysql.com/mysql-apt-config_0.8.29-1_all.deb
         sudo dpkg -i mysql-apt-config_0.8.29-1_all.deb
         sudo apt-get update -y

.github/workflows/ci-taptests-old.yml

@@ -29,7 +29,8 @@ jobs:
         sudo dpkg -i orchestrator-client_3.2.6_amd64.deb
         
         sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 467B942D3A79BD29
-        sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A8D3785C
+        # Ubuntu keyserver serves the expired B7B3B788A8D3785C; fetch renewed key from MySQL.
+        wget -qO - https://repo.mysql.com/RPM-GPG-KEY-mysql-2025 | sudo apt-key add -
         wget https://repo.mysql.com/mysql-apt-config_0.8.29-1_all.deb
         sudo dpkg -i mysql-apt-config_0.8.29-1_all.deb
         sudo apt-get update -y

.github/workflows/ci-taptests-ssl.yml

@@ -95,7 +95,8 @@ jobs:
         sudo dpkg -i orchestrator-client_3.2.6_amd64.deb
         
         sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 467B942D3A79BD29
-        sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A8D3785C
+        # Ubuntu keyserver serves the expired B7B3B788A8D3785C; fetch renewed key from MySQL.
+        wget -qO - https://repo.mysql.com/RPM-GPG-KEY-mysql-2025 | sudo apt-key add -
         wget https://repo.mysql.com/mysql-apt-config_0.8.29-1_all.deb
         sudo dpkg -i mysql-apt-config_0.8.29-1_all.deb
         sudo apt-get update -y

.github/workflows/ci-taptests.yml

@@ -114,7 +114,8 @@ jobs:
         sudo dpkg -i orchestrator-client_3.2.6_amd64.deb
         
         sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 467B942D3A79BD29
-        sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A8D3785C
+        # Ubuntu keyserver serves the expired B7B3B788A8D3785C; fetch renewed key from MySQL.
+        wget -qO - https://repo.mysql.com/RPM-GPG-KEY-mysql-2025 | sudo apt-key add -
         wget https://repo.mysql.com/mysql-apt-config_0.8.29-1_all.deb
         sudo dpkg -i mysql-apt-config_0.8.29-1_all.deb
         sudo apt-get update -y