“Compile” Button Deletes Device on Mobile

**Operating environment/Installation (Hass.io/Docker/pip/etc.):**

Docker esphome/esphome:latest

**ESP (ESP32/ESP8266, Board/Sonoff):**

ESP8266 Nodemcuv2, but probably irrelevant.

**ESPHome version (latest production, beta, dev branch)**

Latest production, v1.15.3

**Affected component:**

N/A

**Description of problem:**
When clicking the “compile” button on my phone, it deletes the device.

[Screen Recording Video](https://imgur.com/a/UI3MlCK).

**Problem-relevant YAML-configuration entries:**
```yaml
N/A
```

**Logs (if applicable):**

```
N/A
```

**Additional information and things you've tried:**
This bug **does** exists in:
- iPhone 11 Pro Max, iOS 13.5, Safari
- iPhone 11 Pro Max, iOS 13.5, Firefox 29
- iPhone 11 Pro Max, iOS 14.3, Safari
- iPhone 11 Pro Max, iOS 14.3, Firefox Daylight 32.0 (3841)

This bug **does not** exist in:
- iPhone 11 Pro Max, iOS 14.4 Safari
- Firefox for Windows 86.0.1, acting as iPhone X/XS iOS 12
- Chrome developer tools running iOS device size and user agent as performed by @jesserockz

The report names no source files or tests. Start by reproducing the Compile-button behavior on the listed iOS versions and compare it with the working iOS 14.4 and desktop emulation cases; done means compiling no longer deletes the device.

Written by the indexing model from the issue text.