Use executeCommand instead of sendText to activate Start Terminal REPL

[Tyriar]

Running & /usr/bin/python3 in the terminal on macOS after starting the REPL:

This is likely because sendText is happening before the prompt is ready. Using the new executeCommand should fix this:

vscode-python/src/client/terminals/codeExecution/terminalCodeExecution.ts

Line 44 in e90b95d

await this.getTerminalService(file, options).sendCommand(command, args);

vscode-python/src/client/common/terminal/service.ts

Line 62 in e90b95d

this.terminal!.sendText(text, true);